View source for Arihant-class submarine

{{Short description|Class of Indian nuclear-powered ballistic missile submarines}}
{{good article}}
{{Use dmy dates|date=March 2020}}
{{Use Indian English|date=February 2020}}
{| {{Infobox ship begin}}
{{Infobox ship image
| Ship image = [[File:Arihant class.png|300px]]
| Ship caption = Profile of Arihant-class submarine
}}
{{Infobox ship class overview
| Name = ''Arihant''
| Builders = [[Naval Dockyard (Visakhapatnam)]]
| Operators = {{navy|India}}
| Class after = {{sclass|S5|submarine|4}}
| In commission range = 2016{{ndash}}present
| Total ships planned = 4
| Total ships completed = 4<ref>{{Cite news|url=https://www.thehindu.com/news/national/indias-fourth-nuclear-submarine-launched-into-water/article68783731.ece|title=India’s fourth nuclear submarine launched into water|newspaper=The Hindu|access-date=29 November 2024|date=November 2024|url-status=live|archive-url=https://web.archive.org/web/20241129092124/https://www.thehindu.com/news/national/indias-fourth-nuclear-submarine-launched-into-water/article68783731.ece|archive-date=29 November 2024}}</ref>
| Total ships active = 3
| Total ships laid up = 
| Total ships lost = 
| Total ships retired = 
| Total ships preserved = 
| Cost = {{INRConvert|40|b|lk=r}} per submarine<ref name="India Today">{{cite news|title=A peek into India's top secret and costliest defence project, nuclear submarines|url=http://indiatoday.intoday.in/story/india-ballistic-missile-submarine-k-6-submarine-launched-drdo/1/1104982.html|access-date=11 December 2017|work=[[India Today]]|date=7 December 2017|url-status=live|archive-url=https://web.archive.org/web/20171211024434/http://indiatoday.intoday.in/story/india-ballistic-missile-submarine-k-6-submarine-launched-drdo/1/1104982.html|archive-date=11 December 2017}}</ref>
}}
{{Infobox ship characteristics
| Hide header = 
| Header caption = 
| Ship type = [[Nuclear submarine|Nuclear-powered]] [[ballistic missile submarine]]
| Ship displacement = *[[INS Arihant|''Arihant'']] & [[INS Arighaat|''Arighaat'']]: {{convert|6000|t|abbr=on}} surfaced<ref name=dna-launch>{{cite news|url=http://www.dnaindia.com/india/report_india-reaches-milestone-with-launch-of-n-powered-submarine_1277227|title=India reaches milestone with launch of n-powered submarine|newspaper=DNA|date=26 July 2007|access-date=24 January 2011|url-status=live|archive-url=https://web.archive.org/web/20160613034034/http://www.newindianexpress.com/nation/EXPRESS-EXCLUSIVE-Maiden-Test-of-Undersea-K-4-Missile-From-Arihant-Submarine/2016/04/09/article3370608.ece|archive-date=13 June 2016}}</ref>
* Aridhaman & S4*: {{convert|7000|t|abbr=on}}<ref name="India Today3" />
| Ship length = Arihant & Arighaat: {{convert|111|m|abbr=on}};<ref name="NuclearArm" /> 
S-4: {{convert|130|m|abbr=on}}<ref name="NuclearArm" /><ref>{{Cite web|url=http://www.hisutton.com/Indian-Navy-S4-SSBN.html|title=H I Sutton - Covert Shores}}</ref>
| Ship beam = {{convert|11|m|abbr=on}}<ref name="NuclearArm" />
| Ship height = 
| Ship draft = {{convert|15|m|abbr=on}}<ref name="NuclearArm" />
| Ship depth = 
| Ship decks = 
| Ship deck clearance = 
| Ship power = 
| Ship propulsion = *1 x CLWR-B1 [[pressurized water reactor]]<ref name="CLWR-B1">{{cite news |title=Founder's Day Speech, Director, BARC |url=http://www.barc.gov.in/presentations/fddir18.pdf |access-date=21 March 2021 |publisher=Bhabha Atmoic Research Centre |date=30 October 2018}}</ref><ref name="clwr_barc">{{cite journal |title=DAE (Excellence in Science, Engineering & Technology) Awards 2010 |journal=BARC Newsletter |date=Sep–Oct 2011 |issue=322 |page=33 |url=http://www.barc.gov.in/publications/nl/2011/2011091009.pdf |access-date=21 March 2021 |archive-date=15 May 2013 |archive-url=https://web.archive.org/web/20130515202113/http://barc.gov.in/publications/nl/2011/2011091009.pdf |url-status=dead }}</ref><ref name="toi-ntriad">{{cite news|url=https://timesofindia.indiatimes.com/india/India-to-achieve-N-arm-triad-in-February/articleshow/11332636.cms|archive-url=https://web.archive.org/web/20130326102050/http://articles.timesofindia.indiatimes.com/2012-01-02/india/30580966_1_ins-arihant-first-indigenous-nuclear-submarine-akula-ii|url-status=live|archive-date=26 March 2013|title = India to achieve N-arm triad in February|newspaper=[[The Times of India]]|date=2 January 2012|access-date=17 March 2016}}</ref> (83 MW)
* 1 × [[propeller shaft|shaft]]
| Ship speed = *''Surfaced:'' {{convert|12|-|15|kn|km/h|abbr=on}}
* ''Submerged:'' {{convert|24|kn|km/h|abbr=on}}
| Ship range = Unlimited except by food supplies
| Ship endurance = 
| Ship test depth = {{convert|450|m|abbr=on}}
| Ship complement = 95
| Ship time to activate = 
| Ship sensors = *[[USHUS (sonar)|USHUS]] sonar
*[[Panchendriya (sonar)|Panchendriya]] sonar
| Ship EW = 
| Ship armament = *[[INS Arihant|''Arihant'']] & [[INS Arighaat|''Arighaat'']]: 12 × [[Sagarika (missile)|K15]] [[SLBM]] ({{cvt|1500|km|disp=or}} range) or 4 × [[K-4 (SLBM)|K-4]] SLBM ({{cvt|3500|km|disp=or}} range)<ref name="India Today3"/>
* ''Aridhaman'' & S4*: 24 × [[Sagarika (missile)|K15]] [[SLBM]] ({{cvt|750|km|disp=or}} range) or 8 × [[K-4 (SLBM)|K-4]] SLBM ({{cvt|3500|km|disp=or}} range)<ref name="India Today3"/> or 8 × [[K-5 (SLBM)|K-5]] SLBM ({{cvt|5000-6000|km|disp=or}} range)<ref name="globalsecurity">{{cite web|first=John|last=Pike|url=http://www.globalsecurity.org/military/world/india/atv-specs.htm|title=Advanced Technology Vessel (ATV)|publisher=globalsecurity.org|date=27 July 2009|access-date=24 January 2011|url-status=live|archive-url=https://web.archive.org/web/20110829062226/http://www.globalsecurity.org/military/world/india/atv-specs.htm|archive-date=29 August 2011}}</ref>
* 6 × 21" (533 mm) torpedo tubes – est 30 charges (torpedoes, cruise missiles or mines)<ref name="globalsecurity"/>
| Ship notes = 
}}
|}

The '''''Arihant''-class''' ({{Lit|Vanquisher of the Enemy}}) is a class of [[Nuclear submarine|nuclear-powered]] [[ballistic missile submarine]]s in service with [[Indian Navy]]. They were developed under the {{INRConvert|900|b|lk=r}} ''Advanced Technology Vessel'' (ATV) project to design and build nuclear-powered submarines.<ref name="India Today"/> These vessels are classified as ''''strategic strike nuclear submarines'''' by India.<ref name=":5">{{Cite web|url=http://pib.gov.in/Pressreleaseshare.aspx?PRID=1551894|title=Prime Minister felicitates crew of INS Arihant on completion of Nuclear Triad|date=5 November 2018|website=Press Information Bureau, Government of India|access-date=2019-09-15}}</ref><ref name=":6">{{Cite news|url=https://economictimes.indiatimes.com/news/defence/ins-arihant-completes-indias-nuclear-triad-pm-modi-felicitates-crew/articleshow/66509959.cms?from=mdr|title=INS Arihant completes India's nuclear triad, PM Modi felicitates crew|date=2018-11-06|work=The Economic Times|access-date=2019-09-15}}</ref>

The lead vessel of the class, {{ship|INS|Arihant}} was laid down in 2004, launched in 2009 and after extensive sea trials was confirmed to be commissioned in August 2016.<ref name=":2">{{Cite news |title=India set to complete N-triad with Arihant commissioning |url=http://timesofindia.indiatimes.com/india/India-set-to-complete-N-triad-with-Arihant-commissioning/articleshow/54907081.cms |url-status=live |archive-url=https://web.archive.org/web/20161020071532/http://timesofindia.indiatimes.com/india/India-set-to-complete-N-triad-with-Arihant-commissioning/articleshow/54907081.cms |archive-date=20 October 2016 |access-date=2016-10-18 |newspaper=The Times of India}}</ref><ref name=":0">{{cite news |url=http://www.newsx.com/national/43966-what-is-ins-arihant |title=What is INS Arihant? |work=NewsX |date=17 October 2016 |author=Ashish Singh |access-date=30 October 2016 |url-status=live |archive-url=https://web.archive.org/web/20161027175800/http://www.newsx.com/national/43966-what-is-ins-arihant |archive-date=27 October 2016}}</ref><ref name="Arihant_ready">{{Cite news|title=India's first nuclear submarine INS Arihant ready or operations, passes deep sea tests|url=http://economictimes.indiatimes.com/news/defence/indias-first-nuclear-submarine-ins-arihant-ready-for-operations-passes-deep-sea-tests/articleshow/51098650.cms|newspaper=[[The Economic Times]]|date=23 February 2016|access-date=23 February 2016|url-status=live|archive-url=https://web.archive.org/web/20160224044357/http://economictimes.indiatimes.com/news/defence/indias-first-nuclear-submarine-ins-arihant-ready-for-operations-passes-deep-sea-tests/articleshow/51098650.cms|archive-date=24 February 2016}}</ref> ''Arihant'' holds the distinction of being the first ballistic missile submarine to have been built by a country other than one of the five [[permanent members of the United Nations Security Council]].<ref name=bbc2>{{cite news|last=Marcus|first=Jonathan|title=Indian-built Arihant nuclear submarine activated|url=https://www.bbc.co.uk/news/world-asia-india-23648310|access-date=12 October 2013|work=[[BBC]]|date=10 August 2013|url-status=live|archive-url=https://web.archive.org/web/20131012083819/http://www.bbc.co.uk/news/world-asia-india-23648310|archive-date=12 October 2013}}</ref> As of 25 October 2024, INS ''Arihant'' and [[INS Arighaat|INS ''Arighaat'']] are already on deep sea patrols.<ref>{{Cite news |date=2024-10-24 |title=India launches its latest nuclear submarine with 75% indigenous tech: Here's what the new S4 means for regional security |url=https://economictimes.indiatimes.com/news/defence/indias-launches-its-latest-nuclear-submarine-with-75-indigenous-tech-heres-what-the-new-s4-means-for-regional-security/articleshow/114547188.cms?from=mdr |access-date=2024-10-26 |work=The Economic Times |issn=0013-0389}}</ref>

==History==
In December 1971, during the [[Indo-Pakistani War of 1971]], [[U.S. President|US President]] [[Richard Nixon]] sent a [[carrier battle group]] named [[Task Force 74]], led by the nuclear-powered {{USS|Enterprise|CVN-65|6}} into the international waters of the [[Bay of Bengal]] in a show of force.<ref>{{Cite news |url=https://www.rbth.com/articles/2011/12/20/1971_war_how_russia_sank_nixons_gunboat_diplomacy_14041|title=1971 War: How Russia sank Nixon's gunboat diplomacy|work=[[Russia Beyond]]|access-date=2016-04-29|url-status=live|archive-url=https://web.archive.org/web/20160613034034/http://www.newindianexpress.com/nation/EXPRESS-EXCLUSIVE-Maiden-Test-of-Undersea-K-4-Missile-From-Arihant-Submarine/2016/04/09/article3370608.ece|archive-date=13 June 2016}}</ref><ref>{{Cite news |url=https://www.thedailystar.net/news/us-fleet-in-bay-of-bengal-a-game-of-deception|title=US Fleet in Bay of Bengal: A game of deception|date=2013-12-15|work=The Daily Star|access-date=2016-04-29}}</ref> Task Force 74 remained in international waters, where it was legally entitled to be. The records of Nixon-Kissinger communications show no contingency nor any plan under which ''Enterprise'' would enter Indian or Pakistani waters, or otherwise intervene in the conflict but it is well known that the duo viewed Pakistan as a strong ally in that region and were silent on [[Bangladesh genocide]] committed by Pakistani military. In response, the [[Soviet Union]] sent a submarine armed with nuclear missiles from [[Vladivostok]] to trail the US task force in support of India.<ref>{{cite news|first=Rakesh|last=Krishnan Simha|url=http://indrus.in/articles/2011/12/20/1971_war_how_russia_sank_nixons_gunboat_diplomacy_14041.html|title=US-Soviet Actions in 1971 Indo-Pakistani War|publisher=Indrus.in|date=20 December 2011|access-date=22 April 2013|work=indrus.in|url-status=live|archive-url=https://web.archive.org/web/20130408214434/http://indrus.in/articles/2011/12/20/1971_war_how_russia_sank_nixons_gunboat_diplomacy_14041.html|archive-date=8 April 2013}}</ref> The event demonstrated the significance of nuclear weapons and ballistic missile submarines to then [[Prime Minister of India|Prime Minister]] [[Indira Gandhi]].<ref name=idr-arihant>{{cite news|url=http://www.indiandefencereview.com/2010/02/arihant-the-annihilator.html|title=Arihant: the annihilator|work=Indian Defence Review|date=25 October 2010|access-date=8 January 2012|url-status=live|archive-url=https://web.archive.org/web/20160613034034/http://www.newindianexpress.com/nation/EXPRESS-EXCLUSIVE-Maiden-Test-of-Undersea-K-4-Missile-From-Arihant-Submarine/2016/04/09/article3370608.ece|archive-date=13 June 2016}}</ref> Following the 1974 [[Smiling Buddha]] nuclear test, the Director of Marine Engineering (DME) at Naval Headquarters initiated a technical feasibility study for an indigenous nuclear propulsion system (Project 932).<ref>{{cite news|first=Premvir|last=Das|url=http://www.business-standard.com/article/opinion/premvir-das-ins-arihant-a-watershed-moment-109073000008_1.html|title=Project 932|newspaper=[[Business Standard]]|date=30 July 2009|access-date=24 April 2013|url-status=live|archive-url=https://web.archive.org/web/20130510021601/http://www.business-standard.com/article/opinion/premvir-das-ins-arihant-a-watershed-moment-109073000008_1.html|archive-date=10 May 2013}}</ref>

The [[Indian Navy]]'s ''Advanced Technology Vessel'' project to design and construct a nuclear submarine took shape in the 1990s.<ref>{{cite web|url=https://fas.org/nuke/guide/india/sub/ssn/index.html|title=India's SNS Project Report|publisher=Fas.org|access-date=24 April 2013|url-status=live|archive-url=https://web.archive.org/web/20121023210937/http://www.fas.org/nuke/guide/india/sub/ssn/index.html|archive-date=23 October 2012}}</ref> Then [[Defence Minister of India|Defence Minister]] [[George Fernandes]] confirmed the project in 1998.<ref>{{cite news|url=http://www.indianexpress.com/res/web/pIe/ie/daily/19980519/13950884.html|title=George defends position on China|work=[[Indian Express]]|date=19 May 1998|access-date=24 February 2011|url-status=live|archive-url=https://web.archive.org/web/20160613034034/http://www.newindianexpress.com/nation/EXPRESS-EXCLUSIVE-Maiden-Test-of-Undersea-K-4-Missile-From-Arihant-Submarine/2016/04/09/article3370608.ece|archive-date=13 June 2016}}</ref> The initial intent of the project was to design nuclear-powered fast attack submarines, though following [[Pokhran-II|nuclear tests conducted by India in 1998]] at [[Pokhran Test Range]] and the Indian pledge of [[no first use]], the project was re-aligned towards the design of a ballistic missile submarine in order to complete India's [[nuclear triad]].<ref name=gs-atv>{{cite web|first=John|last=Pike|url=http://www.globalsecurity.org/military/world/india/atv.htm|title=Advanced Technology Vessel (ATV)|publisher=Globalsecurity.org|access-date=24 January 2011|archive-url= https://web.archive.org/web/20101226032637/http://www.globalsecurity.org/military/world/india/atv.htm| archive-date= 26 December 2010}}</ref><ref name=dna-induction>{{cite news|url=http://www.dnaindia.com/india/report_first-indigenous-nuclear-sub-is-inducted-into-the-navy_1277218|title=First indigenous nuclear sub is inducted into the navy|newspaper=DNA|date=26 July 2009|access-date=24 January 2011|url-status=live|archive-url=https://web.archive.org/web/20090729054243/http://www.dnaindia.com/india/report_first-indigenous-nuclear-sub-is-inducted-into-the-navy_1277218|archive-date=29 July 2009}}</ref><ref>{{cite news|url=http://www.rediff.com/news/2001/feb/16josy4.htm|title=India's nuclear sub still a distant dream|work=[[Rediff]]|date=16 February 2001|access-date=24 January 2011|url-status=live|archive-url=https://web.archive.org/web/20121022063031/http://www.rediff.com/news/2001/feb/16josy4.htm|archive-date=22 October 2012}}</ref>

==Description==
[[File:Prime Minister Narendra Modi receiving the crew of INS Arihant.jpg|left|thumb|PM [[Narendra Modi]] addressing the crew of INS Arihant with a picture of INS Arihant on the wall]]
The ''Arihant''-class submarines are nuclear powered [[ballistic missile submarine]]s built under the ''[[Advanced Technology Vessel]]'' (ATV) project.<ref name="domain-b.com">{{cite web|url=http://www.domain-b.com/defence/general/20090716_indian_indigenous.html|title=Indian indigenous nuclear sub to be unveiled on 26 July: report|publisher=domain-b.com|date=16 July 2009|access-date=24 January 2011|url-status=live|archive-url=https://web.archive.org/web/20110921135024/http://www.domain-b.com/defence/general/20090716_indian_indigenous.html|archive-date=21 September 2011}}</ref><ref>{{cite news|url=http://in.reuters.com/article/companyNews/idINISL35153320090212|title=India nuclear sub project near completion|work=[[Reuters]]|date=12 February 2009|access-date=24 January 2011|url-status=dead|archive-url=https://web.archive.org/web/20160613034034/http://www.newindianexpress.com/nation/EXPRESS-EXCLUSIVE-Maiden-Test-of-Undersea-K-4-Missile-From-Arihant-Submarine/2016/04/09/article3370608.ece|archive-date=13 June 2016}}</ref><ref name="launch1">{{cite news|url=http://news.in.msn.com/national/article.aspx?cp-documentid=3097464|archive-url=https://archive.today/20130104175719/http://news.in.msn.com/national/article.aspx?cp-documentid=3097464|url-status=dead|archive-date=4 January 2013|title=PM to launch indigenous nuke submarine by month-end|date=16 July 2009|work=[[MSN]]|access-date=19 July 2009}}</ref><ref name="launch2">{{cite news|url=http://www.hindu.com/2009/07/19/stories/2009071958490500.htm|title=Indigenous nuclear submarine goes on trial|newspaper=[[The Hindu]]|access-date=19 July 2009|location=Chennai, India|date=19 July 2009|url-status=dead|archive-url=https://web.archive.org/web/20090722084642/http://www.hindu.com/2009/07/19/stories/2009071958490500.htm|archive-date=22 July 2009}}</ref><ref>{{cite news|first=Hari|last=Sud|url=http://www.upiasia.com/Security/2009/08/14/indias_nuclear_submarine_and_the_indian_ocean/7676/|title=India's nuclear submarine and the Indian Ocean|publisher=upiasia.com|date=14 August 2009|access-date=24 January 2011|url-status=live|archive-url=https://web.archive.org/web/20110728133202/http://www.upiasia.com/Security/2009/08/14/indias_nuclear_submarine_and_the_indian_ocean/7676/|archive-date=28 July 2011}}</ref><ref>{{cite news|url=http://blogs.reuters.com/india/2009/07/31/indias-nuclear-submarine-dream-still-miles-to-go/|work=[[Reuters]]|title=India's nuclear submarine dream, still miles to go|date=31 July 2009|access-date=24 January 2011|url-status=dead|archive-url=https://web.archive.org/web/20110525082031/http://blogs.reuters.com/india/2009/07/31/indias-nuclear-submarine-dream-still-miles-to-go|archive-date=25 May 2011}}</ref> They will be the first nuclear submarines designed and built by India.<ref name=it-finaltest>{{cite news|url=http://indiatoday.intoday.in/story/Final+test+of+K-15+ballistic+missile+on+Tuesday/1/5002.html|title=Final test of K-15 ballistic missile on Tuesday|date=25 February 2008|access-date=24 January 2012|url-status=live|archive-url=https://web.archive.org/web/20120921085654/http://indiatoday.intoday.in/story/Final%20test%20of%20K-15%20ballistic%20missile%20on%20Tuesday/1/5002.html|archive-date=21 September 2012}}</ref> The submarines are {{convert|111|m|abbr=on|}} [[Length overall|long]] with a [[Beam (nautical)|beam]] of {{convert|11|m|abbr=on}}, a [[Draught (ship)|draught]] of {{convert|15|m|abbr=on|}}, displacement of {{convert|6000|t}}.<ref name="NuclearArm">{{cite magazine|last=Subramanian|first=T.S.|date=15 August 2009|title=Nuclear Arm|url=http://www.hindu.com/fline/fl2617/stories/20090828261702500.htm|magazine=The Frontline|volume=26|issue=17|archive-url=https://web.archive.org/web/20130526061306/http://www.hindu.com/fline/fl2617/stories/20090828261702500.htm|archive-date=26 May 2013|access-date=2 June 2015|url-status=live}}</ref> The complement is about 95, including officers and sailors.<ref name="navaltech">{{cite web|url=http://www.naval-technology.com/projects/arihant-class/|title=SSBN Arihant Class Submarine, India|publisher=naval-technology.com|access-date=22 April 2013|url-status=live|archive-url=https://web.archive.org/web/20130502115614/http://www.naval-technology.com/projects/arihant-class|archive-date=2 May 2013}}</ref> The boats are powered by a single seven blade propeller powered by an 83 MW [[pressurised water reactor]] and can achieve a maximum speed of {{convert|12|-|15|kn|km/h}} when surfaced and {{convert|24|kn|km/h}} when submerged.<ref name="navaltech"/><ref>{{Cite web|url=https://www.naval-technology.com/projects/arihant-class/#:~:text=Arihant%20design,up%20to%2024kt%20when%20submerged.|title = Arihant Class Submarine - Naval Technology}}</ref>
[[File:B05 SLBM.jpg|thumb|[[Sagarika (missile)|Sagarika SLBM]]]]
The submarines have four launch tubes in their hump and can carry up to twelve [[Sagarika (missile)|K-15 Sagarika]] missiles with one warhead each (with a range of {{convert|750|km|abbr=on|disp=or}}) or four [[K-4 (SLBM)|K-4]] missiles (with a range of {{convert|3500|km|abbr=on|disp=or}}).<ref name=it-undersea>{{cite news|url=http://indiatoday.intoday.in/story/The+secret+undersea+weapon/1/3659.html|title=The secret undersea weapon|work=[[India Today]]|date=17 January 2008|access-date=8 January 2012|url-status=live|archive-url=https://web.archive.org/web/20111231120048/http://indiatoday.intoday.in/story/The%20secret%20undersea%20weapon/1/3659.html|archive-date=31 December 2011}}</ref><ref>{{Cite news|url=https://wap.business-standard.com/article-amp/specials/how-india-s-pride-ins-arihant-was-built-113081100745_1.html|title=How Indias pride INS Arihant was built|newspaper=Business Standard India|date=12 August 2013|last1=Malhotra|first1=Jyoti}}</ref><ref name=it-secretk>{{cite news|url=http://indiatoday.intoday.in/site/story/the-secret-k-missile-family/1/120488.html|work=[[India Today]]|title=The secret 'K' missile family|date=20 November 2010|access-date=8 January 2012|url-status=live|archive-url=https://web.archive.org/web/20110807075726/http://indiatoday.intoday.in/site/story/the-secret-k-missile-family/1/120488.html|archive-date=7 August 2011}}</ref> The third and fourth submarines will have a larger configuration, carrying twenty-four K-15 Sagarika or eight K-4 missiles.<ref name="India Today3">{{cite news|url=http://indiatoday.intoday.in/story/india-ballistic-missile-submarine-k-6-submarine-launched-drdo/1/1104982.html|title=A peek into India's top secret and costliest defence project, nuclear submarines|last=Unnithan|first=Sandeep|date=7 December 2017|work=[[India Today]]|access-date=11 December 2017|url-status=live|archive-url=https://web.archive.org/web/20171211024434/http://indiatoday.intoday.in/story/india-ballistic-missile-submarine-k-6-submarine-launched-drdo/1/1104982.html|archive-date=11 December 2017}}</ref> The Indian Navy will train on {{INS|Chakra|2011|6}}, an Akula-class submarine leased from Russia in 2012.<ref name=autogenerated1>{{cite web|url=http://www.globalsecurity.org/military/world/india/atv.htm|title=Arihant – Advanced Technology Vessel (ATV)|publisher=Global Security|access-date=8 January 2012|url-status=live|archive-url=https://web.archive.org/web/20120110182851/http://www.globalsecurity.org/military/world/india/atv.htm|archive-date=10 January 2012}}</ref><ref name=it-setsail>{{cite news|url=http://indiatoday.intoday.in/story/leased-russian-n-submarine-to-set-sail-for-india-this-month-end/1/164449.html|title=Leased Russian n-submarine to set sail for India this month end|date=15 December 2011|access-date=8 January 2012|url-status=live|archive-url=https://web.archive.org/web/20120105102758/http://indiatoday.intoday.in/story/leased-russian-n-submarine-to-set-sail-for-india-this-month-end/1/164449.html|archive-date=5 January 2012}}</ref>

The submarine's K-15 missiles can reach most of Pakistan and its K-4 can target all of Pakistan.<ref name=nathan/> The K-4 may also be capable of targeting [[Beijing]], but would need to be in the northern most waters of [[Bay of Bengal]].<ref name=nathan/> Deployment of the Arihant to the Pacific Ocean is unlikely given the submarine's noise issues.<ref name=nathan>{{cite journal|title=The Arihant-Class SSBN and the Advent of Sea-Based Nuclear Forces in India, China, and Pakistan|author=Nathan Powell|journal=Project on Nuclear Issues: A Collection of Papers from the 2017 Conference Series and Nuclear Scholars Initiative|pages=141–142}}</ref>

==Development==
[[File:Arihant 1.svg|thumb|right|Conceptual drawing of INS ''Arihant'']]
The submarines are powered by a [[pressurised water reactor]] with [[highly enriched uranium]] fuel.<ref name=toi-20090717>{{cite news|url=https://timesofindia.indiatimes.com/india/India-set-to-launch-nuclear-powered-submarine/articleshow/4787167.cms|newspaper=[[The Times of India]]|first=Rajat|last=Pandit|title=India set to launch nuclear-powered submarine|date=17 July 2009|access-date=17 March 2016|url-status=live|archive-url=https://web.archive.org/web/20160613034034/http://www.newindianexpress.com/nation/EXPRESS-EXCLUSIVE-Maiden-Test-of-Undersea-K-4-Missile-From-Arihant-Submarine/2016/04/09/article3370608.ece|archive-date=13 June 2016}}</ref><ref>{{cite news|url=http://www.hindu.com/seta/2009/11/05/stories/2009110551721200.htm|title=High fissile fuel in nuclear submarine lasts long|newspaper=[[The Hindu]]|date=5 November 2009|access-date=17 March 2016|location=Chennai, India|url-status=dead|archive-url=https://web.archive.org/web/20121105132403/http://www.hindu.com/seta/2009/11/05/stories/2009110551721200.htm|archive-date=5 November 2012}}</ref> The miniaturised version of the reactor was designed and built by the [[Bhabha Atomic Research Centre]] (BARC) at the [[Indira Gandhi Centre for Atomic Research]] (IGCAR) in [[Kalpakkam]].<ref name=hindu-indiandesign>{{cite news|url=http://www.hindu.com/2009/08/16/stories/2009081655260900.htm|title=INS Arihant is an Indian design: Anil Kakodkar|newspaper=[[The Hindu]]|date=16 August 2009|access-date=17 March 2016|location=Chennai, India|url-status=live|archive-url=https://web.archive.org/web/20160613034034/http://www.newindianexpress.com/nation/EXPRESS-EXCLUSIVE-Maiden-Test-of-Undersea-K-4-Missile-From-Arihant-Submarine/2016/04/09/article3370608.ece|archive-date=13 June 2016}}</ref> It included a {{convert|42|m|ft|adj=on}} section of the submarine's pressure hull containing the shielding tank with water and the reactor, a control room, as well as an auxiliary control room for monitoring safety parameters.<ref>{{cite news|url=http://www.telegraphindia.com/1090803/jsp/nation/story_11313999.jsp|title=Unveiled: Arihant's elder brother|work=Telegraph India|date=3 August 2009|access-date=17 March 2016|location=Calcutta, India|first=G.C.|last=Shekhar|url-status=dead|archive-url=https://web.archive.org/web/20160117011504/http://www.telegraphindia.com/1090803/jsp/nation/story_11313999.jsp|archive-date=17 January 2016}}</ref> The prototype reactor became critical on 11 November 2003 and was declared operational on 22 September 2006.<ref name=idr-arihant/> Successful operation of the prototype for three years enabled the production version of the reactor for ''Arihant''.<ref name="pwr_1">{{cite news|url=http://www.hindu.com/2009/08/03/stories/2009080353810100.htm |title=PWR building shows indigenous capability |first=T.S. |last=Subramanian |date=2 August 2009 |newspaper=[[The Hindu]] |access-date=17 March 2016 |location=Chennai, India |url-status=dead |archive-url=https://web.archive.org/web/20090808043941/http://www.hindu.com/2009/08/03/stories/2009080353810100.htm |archive-date=8 August 2009}}</ref><ref name="pwr_2">{{cite news|url=http://www.hindustantimes.com/StoryPage/StoryPage.aspx?sectionName=HomePage&id=5721403d-8f66-43e2-92c4-4f3148032565&Headline=Arihant+propulsion+reactor+unveiled|title=Arihant propulsion reactor unveiled|first=M.R.|last=Venkatesh|date=2 August 2009|access-date=17 March 2016|newspaper=[[Hindustan Times]]}}{{dead link|date=August 2021|bot=medic}}{{cbignore|bot=medic}}</ref> The reactor subsystems were tested at the Machinery Test Center in [[Visakhapatnam]].<ref>{{cite web|url=http://www.nrbdrdo.res.in/nstl.html|title=Naval Research Board|publisher=DRDO|access-date=17 March 2016|url-status=dead|archive-url=https://web.archive.org/web/20160316234337/http://www.nrbdrdo.res.in/nstl.html|archive-date=16 March 2016}}</ref> Facilities for loading and replacing the fuel cores of the naval reactors in berthed submarines were also established.<ref name=idr-arihant/> The prototype 83 MW light water reactor that was installed at [[Kalpakkam]] by BARC is codenamed S1 and is used to train nuclear submariners.<ref name="India Today3" />

In 2007, then finance minister [[P. Chidambaram]], who was a member of the political committee which monitors the ATV programme, questioned the huge amount of money being spent on submarines with just 4 missile launch tubes. Hence, the ATV project team tweaked the Arihant design by adding a 10-metre-long section for four more [[K-4 (missile)|K-4]] SLBMs to be integrated into the boat codenamed S4. After it became evident that the larger [[S5-class submarine|S5 class]] of SSBNs will take more time to develop, an additional unit, codenamed S4*, was sanctioned in 2012 to ensure that the production line doesn't go idle.<ref name="India Today3" /> Hence, the final two ships INS Aridhaman (S4) and S4* in the class are expected to be larger, displacing over 1,000 tonnes more than the ''Arihant''<ref name="India Today32">{{cite news |last=Unnithan |first=Sandeep |date=7 December 2017 |title=A peek into India's top secret and costliest defence project, nuclear submarines |url=http://indiatoday.intoday.in/story/india-ballistic-missile-submarine-k-6-submarine-launched-drdo/1/1104982.html |url-status=live |archive-url=https://web.archive.org/web/20171211024434/http://indiatoday.intoday.in/story/india-ballistic-missile-submarine-k-6-submarine-launched-drdo/1/1104982.html |archive-date=11 December 2017 |access-date=11 December 2017 |work=[[India Today]]}}</ref> and have 8 missile launch tubes to carry up to 24 K15 or 8 K4 or K5 and a more powerful pressurized water reactor than INS ''Arihant''.<ref>{{Cite web |last=Mundhra |first=Shreya |date=2022-01-02 |title=Boosting Indian Navy's Firepower, DRDO Launches Nuclear Submarine With 'Vertical Launch System' |url=https://www.eurasiantimes.com/indian-navy-launches-3rd-arihant-class-nuclear-submarine/ |access-date=2024-02-01 |website=Latest Asian, Middle-East, EurAsian, Indian News |language=en-US}}</ref>

On 24 December 2009, the [[Hindustan Shipyard]], located at Visakhapatnam, was transferred from the [[Ministry of Shipping (India)|Ministry of Shipping]] to the [[Ministry of Defence (India)|Ministry of Defence]] to support the construction of ''Arihant''-class submarine programme. This would help in utilising the shipyard's infrastructure in the project.<ref name="Sharma">{{cite web |author=Sharma |first=Suman |date=12 June 2010 |title=Navy creating a new base for nuke submarines |url=http://www.dnaindia.com/india/report_navy-creating-a-new-base-for-nuke-submarines_1395220 |access-date=11 June 2010 |work= |publisher=Daily News & Analysis}}</ref><ref>{{cite news |date=24 December 2009 |title=On national security interests, Govt moves Hindustan Shipyard to Defence ministry |url=https://timesofindia.indiatimes.com/india/On-national-security-interests-Govt-moves-Hindustan-Shipyard-to-Defence-ministry/articleshow/5373703.cms |url-status=live |archive-url=https://web.archive.org/web/20120926143826/http://articles.timesofindia.indiatimes.com/2009-12-24/india/28091316_1_hindustan-shipyard-defence-ministry-hsl |archive-date=26 September 2012 |access-date=11 June 2010 |work=[[The Times of India]] |agency=PTI}}</ref>

The detailed engineering of the design was implemented{{when|date=April 2021}} at [[Larsen & Toubro]]'s submarine design centre at their [[Hazira]] shipbuilding facility.<ref>{{cite press release|url=http://www.larsentoubro.com/lntcorporate/LnT_PRS/PDF/L&TPressRelease-Jul26-2009.pdf|title=Larsen and Toubro's Contribution to Arihant-class submarine|date=26 July 2009|access-date=17 March 2016}}{{Dead link|date=November 2019 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> [[Tata Power SED]] built the control systems for the submarine.<ref>{{cite web|title=India's first Indigenous nuclear submarine |url=http://www.jeywin.com/blog/arihant-–-india’s-first-indigenous-nuclear-submarine/|publisher=Jeywin|access-date=24 April 2013 |url-status=dead|archive-url=https://archive.today/20130217054406/http://www.jeywin.com/blog/arihant-%E2%80%93-india%E2%80%99s-first-indigenous-nuclear-submarine/|archive-date=17 February 2013 }}</ref> The steam turbines and associated systems integrated with the reactor were supplied by [[Walchandnagar Industries]].<ref name=dna-ppp>{{cite news|url=http://www.dnaindia.com/india/report_private-sector-played-a-major-role-in-arihant_1277435|title=Private sector played a major role in Arihant|newspaper=DNA|date=27 April 2009|access-date=17 March 2016|url-status=live|archive-url=https://web.archive.org/web/20120916225008/http://www.dnaindia.com/india/report_private-sector-played-a-major-role-in-arihant_1277435|archive-date=16 September 2012}}</ref> The lead vessel underwent a long and extensive process of testing after its launch in July 2009.<ref>{{cite news|url=http://www.hindu.com/2009/07/27/stories/2009072755801000.htm|location=Chennai, India|newspaper=[[The Hindu]]|title=Nuclear submarine Arihant to be fitted with K-15 ballistic missiles|date=27 July 2009|access-date=17 March 2016|url-status=live|archive-url=https://web.archive.org/web/20160613034034/http://www.newindianexpress.com/nation/EXPRESS-EXCLUSIVE-Maiden-Test-of-Undersea-K-4-Missile-From-Arihant-Submarine/2016/04/09/article3370608.ece|archive-date=13 June 2016}}</ref> The propulsion and power systems were tested with high-pressure steam trials followed by harbor-acceptance trials that included submersion tests by flooding its ballast tanks and controlled dives to limited depths.<ref name=toi-homemade>{{cite news|url=https://timesofindia.indiatimes.com/india/Home-made-nuke-sub-INS-Arihant-to-be-inducted-in-2-years/articleshow/5293123.cms|title=Home-made nuke sub INS Arihant to be inducted in 2 years|newspaper=[[The Times of India]]|date=3 December 2009|access-date=17 March 2016|url-status=live|archive-url=https://web.archive.org/web/20160613034034/http://www.newindianexpress.com/nation/EXPRESS-EXCLUSIVE-Maiden-Test-of-Undersea-K-4-Missile-From-Arihant-Submarine/2016/04/09/article3370608.ece|archive-date=13 June 2016}}</ref> INS ''Arihant''{{'}}s reactor went [[Criticality (status)|critical]] for the first time on 10 August 2013.<ref>{{cite news|url=http://www.thehindu.com/sci-tech/technology/k15-all-set-to-join-arihant/article4242325.ece|title=K-15 all set to join Arihant|newspaper=[[The Hindu]]|date=27 December 2012|access-date=17 March 2016|url-status=live|archive-url=https://web.archive.org/web/20160117011505/http://www.thehindu.com/sci-tech/technology/k15-all-set-to-join-arihant/article4242325.ece|archive-date=17 January 2016}}</ref> On 13 December 2014, the submarine set off for its extensive sea trials.<ref>{{cite news|url=http://economictimes.indiatimes.com/news/politics-and-nation/indias-nuclear-submarine-arihant-flagged-off-for-sea-trials/articleshow/45526418.cms|title=India's nuclear submarine Arihant flagged off for sea trials|newspaper=[[The Economic Times]]|date=13 December 2014|access-date=15 December 2014|url-status=live|archive-url=https://web.archive.org/web/20160613034034/http://www.newindianexpress.com/nation/EXPRESS-EXCLUSIVE-Maiden-Test-of-Undersea-K-4-Missile-From-Arihant-Submarine/2016/04/09/article3370608.ece|archive-date=13 June 2016}}</ref><ref>{{cite news|url=http://www.thehindu.com/news/cities/Visakhapatnam/ins-arihant-sails-out-of-harbour/article6693951.ece?homepage=true|title=INS Arihant sails out of harbour|newspaper=[[The Hindu]]|date=13 December 2014|access-date=15 December 2014|url-status=live|archive-url=https://web.archive.org/web/20160117011504/http://www.thehindu.com/news/cities/Visakhapatnam/ins-arihant-sails-out-of-harbour/article6693951.ece?homepage=true|archive-date=17 January 2016}}</ref> The first boat of the class, {{INS|Arihant}}, was commissioned in August 2016.<ref name="toi-ntriad2">{{cite news |date=2 January 2012 |title=India to achieve N-arm triad in February |url=https://timesofindia.indiatimes.com/india/India-to-achieve-N-arm-triad-in-February/articleshow/11332636.cms |url-status=live |archive-url=https://web.archive.org/web/20130326102050/http://articles.timesofindia.indiatimes.com/2012-01-02/india/30580966_1_ins-arihant-first-indigenous-nuclear-submarine-akula-ii |archive-date=26 March 2013 |access-date=17 March 2016 |newspaper=[[The Times of India]]}}</ref><ref name=":2" /><ref>{{Cite news |title=Satisfied with nuclear sub Arihant trials: Navy Chief |url=http://www.tribuneindia.com/news/satisfied-with-nuclear-sub-arihant-trials-navy-chief/74351.html |url-status=live |archive-url=https://web.archive.org/web/20160304110613/http://www.tribuneindia.com/news/satisfied-with-nuclear-sub-arihant-trials-navy-chief/74351.html |archive-date=4 March 2016 |access-date=17 March 2016 |newspaper=Tribune India}}</ref> On 5 November 2018, INS Arihant completed its first deterrence patrol.<ref name=":5" /><ref name=":6" />

In December 2014, the work on a second nuclear reactor began and {{INS|Arighaat}} started [[Sea trial|sea trials]] in 2017. As per reports released in August 2024, INS Arighaat was commissioned before October 2024.<ref name=":82">{{Cite news |date=2024-08-11 |title=India 'fully ready' to add to fleet 2nd submarine with nuclear-tipped missiles |url=https://timesofindia.indiatimes.com/india/india-fully-ready-to-add-to-fleet-2nd-sub-with-n-tipped-missiles/articleshow/112433199.cms |access-date=2024-08-11 |work=The Times of India |issn=0971-8257}}</ref><ref name=":72">{{Cite news |date=2024-08-11 |title=India set to commission its second nuclear-missile submarine |url=https://economictimes.indiatimes.com/news/defence/india-set-to-commission-its-second-nuclear-missile-submarine/articleshow/112438432.cms?from=mdr |access-date=2024-08-12 |work=The Economic Times |issn=0013-0389}}</ref> On 29 August 2024, after extensive trials and upgrades INS Arighaat was formally commissioned.<ref name=":9" />

INS Aridhaman (S4) was launched in November 2021.<ref name="India Today33">{{cite news |last=Unnithan |first=Sandeep |date=7 December 2017 |title=A peek into India's top secret and costliest defence project, nuclear submarines |url=http://indiatoday.intoday.in/story/india-ballistic-missile-submarine-k-6-submarine-launched-drdo/1/1104982.html |url-status=live |archive-url=https://web.archive.org/web/20171211024434/http://indiatoday.intoday.in/story/india-ballistic-missile-submarine-k-6-submarine-launched-drdo/1/1104982.html |archive-date=11 December 2017 |access-date=11 December 2017 |work=[[India Today]]}}</ref><ref name="THE NEW INDIAN EXPRESS2">{{cite news |title=DRDO on long range Pralay, K5 to stalemate China soon |url=https://www.newindianexpress.com/states/odisha/2018/dec/15/maiden-trial-of-pralay-k5-likely-soon-1911623.html |access-date=15 December 2018 |publisher=THE NEW INDIAN EXPRESS}}</ref> The submarine begun sea trials in 2022.<ref>{{Cite web |title=Third Indian N-powered ballistic missile submarine to be inducted this year |url=https://www.deccanherald.com/india/third-indian-n-powered-ballistic-missile-submarine-to-be-inducted-this-year-3387338?utm_source=whatsapp&utm_medium=referral&utm_campaign=socialshare |access-date=2025-02-04 |website=Deccan Herald |language=en}}</ref> On 30 August 2024, a report suggested that this submarine will be commissioned in the next 6 months.<ref name=":7">{{Cite news |date=2024-08-30 |title=Amid China standoff, India set to boost naval power with 3rd N-sub in 6 months |url=https://timesofindia.indiatimes.com/india/amid-china-standoff-india-set-to-boost-naval-power-with-3rd-n-sub-in-6-months/articleshow/112905487.cms |access-date=2024-08-30 |work=The Times of India |issn=0971-8257}}</ref>

The fourth submarine of the class, with an indigenous content of 75% and equipped with K4 missiles, was launched on 16 October 2024.<ref name=":8">{{Cite news |last=Gupta |first=Shishir |date=22 October 2024 |title=India Launches 4th nuclear-missile submarine |url=https://www.hindustantimes.com/india-news/india-launches-4th-nuclear-missile-submarine-101729560730642.html |access-date=22 October 2024 |work=[[Hindustan Times]]}}</ref>

In August 2024, it was reported that a fifth Arihant-class submarine which will be the third of S4 subclass is to be constructed.<ref>{{Cite news |last=Kumar |first=Bhaswar |date=30 August 2024 |title='More advanced': 10 key points on India's second nuclear sub INS Arighat |url=https://www.business-standard.com/external-affairs-defence-security/news/more-advanced-10-key-points-on-india-s-second-nuclear-sub-ins-arighat-124083000620_1.html |access-date=28 September 2024 |work=[[Business Standard]]}}</ref>

==Ships in class==

{| class="wikitable"
|-
! Name
! Pennant
! Displacement (surfaced)
! Laid down
! Launch
! Sea Trials  Begins
!Sea Trials Completed
! Commission
! Status
|-
| {{ship|INS|Arihant}} (S2)<ref name="India Today3" /><ref>{{Cite news|url=https://www.thehindu.com/news/national/ins-arihant-may-be-of-limited-utility/article6709623.ece|title=INS Arihant may be of limited utility|last=Anandan|first=S.|date=2014-12-20|work=The Hindu|access-date=2019-06-30|language=en-IN|issn=0971-751X}}</ref>
| SSBN 80<ref>{{Cite news |date=2018-11-06 |title=20 years after Pokhran II, India makes giant nuclear leap |url=https://www.hindustantimes.com/india-news/20-years-after-pokhran-ii-india-makes-giant-nuclear-leap/story-GlCezZbc4J7VpRshfF4RYJ.html |access-date=2018-11-25 |work=[[Hindustan Times]] |language=en}}</ref>
| rowspan="2" | 6,000 tonnes
| 2004<ref name="jfs-1617">{{cite book|editor1-last=Saunders|editor1-first=Stephen|editor1-mask=Commodore Stephen Saunders|title=Jane's Fighting Ships 2016–2017|date=2016|publisher=Jane's Information Group|location=Coulsdon|isbn=978-0710631855|page=336|edition=119th|chapter=India}}</ref>
| 26 July 2009
| 13 December 2014<ref name="INS Arihant sails out of harbour">{{cite news|url=http://www.thehindu.com/news/cities/Visakhapatnam/ins-arihant-sails-out-of-harbour/article6693951.ece?homepage=true|title=INS Arihant sails out of harbor|newspaper=[[The Hindu]]|date=13 December 2014|access-date=22 December 2014|url-status=live|archive-url=https://web.archive.org/web/20160117011504/http://www.thehindu.com/news/cities/Visakhapatnam/ins-arihant-sails-out-of-harbour/article6693951.ece?homepage=true|archive-date=17 January 2016}}</ref>
|23 February 2016<ref>{{Cite news|last=Pubby|first=Manu|title=India's first nuclear submarine INS Arihant ready for operations, passes deep sea tests|work=The Economic Times|url=https://economictimes.indiatimes.com/news/defence/indias-first-nuclear-submarine-ins-arihant-ready-for-operations-passes-deep-sea-tests/articleshow/51098650.cms|access-date=2021-09-09}}</ref>
| August 2016
| rowspan="2" | Active
|-
| {{ship|INS|Arighaat}} (S3)<ref>{{Cite web|url=https://www.vifindia.org/2018/december/11/india-s-nuclear-triad-is-now-fully-operational|title=India's Nuclear Triad is now Fully Operational|date=2018-12-11|website=Vivekananda International Foundation|language=en|access-date=2019-07-02}}</ref>
|SSBN 81
| 2009<ref name="jfs-1617"/>
| 19 November 2017<ref name="bigger_nuclear_sub">{{Cite news|last1=Peri|first1=Dinakar|last2=Joseph|first2=Josy|url=http://www.thehindu.com/news/national/a-bigger-nuclear-submarine-is-coming/article19862549.ece|title=A bigger nuclear submarine is coming|date=2017-10-15|newspaper=The Hindu|access-date=2017-10-15|url-status=live|archive-url=https://web.archive.org/web/20180303201420/http://www.thehindu.com/news/national/a-bigger-nuclear-submarine-is-coming/article19862549.ece|archive-date=3 March 2018}}</ref><ref>{{Cite web|last=Bedi|first=Rahul|url=http://www.janes.com/article/76315/india-quietly-launches-second-ssbn|title=India quietly launches second SSBN|work=IHS Jane's Defence Weekly|date=2017-12-11|url-status=dead|archive-url=https://web.archive.org/web/20171212031838/http://www.janes.com/article/76315/india-quietly-launches-second-ssbn|archive-date=12 December 2017|access-date=11 December 2017}}</ref>
|8 January 2018<ref>{{Cite news|last=Joseph|first=Dinakar Peri & Josy|date=2018-01-08|title=INS Arihant left crippled after 'accident' 10 months ago|language=en-IN|work=The Hindu|url=https://www.thehindu.com/news/national/ins-arihant-left-crippled-after-accident-10-months-ago/article22392049.ece|access-date=2021-09-09|issn=0971-751X}}</ref>
|March 2021<ref>{{Cite web|title=Vikrant, nuclear submarine commissioning to ring in 75th Independence anniversary celebrations|url=https://www.indiatoday.in/india-today-insight/story/vikrant-nuclear-submarine-commissioning-to-ring-in-75th-independence-anniversary-celebrations-1838057-2021-08-08|access-date=2021-09-09|website=India Today|language=en}}</ref>
| 29 August 2024<ref name=":9">{{cite web |date=2024-08-29 |title=Second Arihant-Class submarine ‘INS Arighaat’ commissioned into Indian Navy in the presence of Raksha Mantri in Visakhapatnam |url=https://pib.gov.in/PressReleasePage.aspx?PRID=2049870 |access-date=29 August 2024 |website=Press Information Bureau}}</ref><ref name=":10">{{Cite news |date=2024-08-29 |title=India commissions INS Arighat: Know all about Navy's 2nd nuclear-powered submarine |url=https://timesofindia.indiatimes.com/india/india-commissions-ins-arighat-know-all-about-navys-2nd-nuclear-powered-submarine/articleshow/112900556.cms |access-date=2024-08-29 |work=The Times of India |issn=0971-8257}}</ref>
|-
| {{ship|INS|Aridhaman}} (S4)<ref name=":1">{{Cite magazine |last=Saurav |first=Jha |title=India's Undersea Deterrent |url=https://thediplomat.com/2016/03/indias-undersea-deterrent/ |url-status=live |archive-url=https://web.archive.org/web/20160408081504/https://thediplomat.com/2016/03/indias-undersea-deterrent/ |archive-date=8 April 2016 |access-date=2016-04-09 |magazine=The Diplomat}}</ref>
|SSBN 82
| rowspan="2" |7,000 tonnes
| 2018<ref name = "hindu1">{{cite news |title=A bigger nuclear submarine is coming |url= https://www.thehindu.com/news/national/a-bigger-nuclear-submarine-is-coming/article19862549.ece |date=2017|website=www.thehindu.com |publisher=[[The Hindu]] |access-date=25 June 2025}}</ref>
| 23 November 2021<ref name=":4">{{Cite news |date=2021-12-31|title=India Quietly Launches 3rd Arihant-class Nuclear-powered Submarine, Can Carry 8 Ballistic Missiles: Report|url=https://www.news18.com/news/india/india-quietly-launches-3rd-arihant-class-nuclear-powered-submarine-can-carry-8-ballistic-missiles-report-4610366.html|access-date=2021-12-31|work=News18|language=en}}</ref>
|
|
|2025 ''(expected)''<ref name="dh">{{cite news |title=Third Indian N-powered ballistic missile submarine to be inducted this year |url= https://www.deccanherald.com/india/third-indian-n-powered-ballistic-missile-submarine-to-be-inducted-this-year-3387338 |date=2025 |website=www.deccanherald.com |publisher=[[Deccan Herald]] |access-date=25 June 2025}}</ref>
|Under Sea Trials
|-
| S4* (codename)<ref name=":1" />
|
|
|16 October 2024<ref>{{Cite news |last=Peri |first=Dinakar |date=2024-10-22 |title=India’s fourth nuclear submarine launched into water |url=https://www.thehindu.com/news/national/indias-fourth-nuclear-submarine-launched-into-water/article68783731.ece |access-date=2024-11-29 |work=The Hindu |language=en-IN |issn=0971-751X}}</ref>
|
|
|
| Launched
|}

== Timeline ==
{| class="wikitable sortable"  
|- 
! style=width:110px; | '''Date'''
!  '''Event'''
|- style="background:#f4f9ff;"
| 19 May 1998 || Confirmation of ATV project by the then Defence Minister [[George Fernandes]]
|- style="background:#f4f9ff;"
| 11 November 2003 || Prototype nuclear reactor becomes critical
|- style="background:#f4f9ff;"
| 22 September 2006 || Nuclear reactor is declared operational
|-
|2007
|Design of S4 is modified to allow four more launch tubes.<ref name="India Today3" />
|- style="background:#f4f9ff;"
| 26 July 2009|| Lead vessel of the class, {{INS|Arihant}}, is formally launched
|-
|2012
|Additional unit S4* is cleared to avoid idling of production line.<ref name="India Today3" />
|- style="background:#f4f9ff;"
| 10 August 2013|| ''Arihant''{{'}}s on-board nuclear reactor attains [[Nuclear reactor physics#Criticality|criticality]]
|- style="background:#f4f9ff;"
| 13 December 2014|| INS ''Arihant'' begins extensive sea & weapons trials
|- style="background:#f4f9ff;"
| 25 November 2015|| INS ''Arihant'' successfully test-fired dummy B5 missile
|- style="background:#f4f9ff;"
| 31 March 2016|| INS ''Arihant'' successfully test-fired K4 missile
|- style="background:#f4f9ff;"
| August 2016|| INS ''Arihant'' commissioned.<ref name=":2" />
|-
|19 November 2017
|[[INS Arighaat|INS ''Arighaat'']] launched<ref name="India Today"/>
|-
|8 January 2018
|INS ''Arighaat'' to begin sea trials<ref name=":3">{{Cite news |url=http://theprint.in/2017/08/24/exclusive-aridaman-indias-second-nuclear-armed-submarine-ready-launch/|title=Exclusive: 'Aridaman', India's second nuclear-armed submarine, is ready for launch|last=Pubby|first=Manu|date=2017-08-24|work=ThePrint|archive-url=https://web.archive.org/web/20170825060616/http://theprint.in/2017/08/24/exclusive-aridaman-indias-second-nuclear-armed-submarine-ready-launch/|archive-date=25 August 2017|url-status=live|access-date=2017-08-24}}</ref>
|-
|5 November 2018
|INS Arihant completed its first deterrence patrol<ref>{{Cite news |date=2018-11-05 |title=India's nuclear triad is complete with INS Arihant ending its first deterrence patrol |language=en-IN |work=The Hindu |url=https://www.thehindu.com/news/national/ins-arihant-completes-deterrence-patrol-india-declares-nuclear-traid-operational/article25425436.ece |access-date=2023-03-14 |issn=0971-751X}}</ref>
|-
|March 2021
|''INS Arighaat's'' sea trials are completed.
|-
|November 2021
|S4 is speculated to be launched.<ref name=":4" />
|-
|29 August 2024
|INS ''Arighaat'' officially commissioned.<ref name=":9" />
|-
|16 October 2024
|S4* launched<ref name=":8" />
|-
|2025
|S4 commissioning expected<ref name="dh" />
|}

==See also==
* [[Future of the Indian Navy]]
* [[List of active Indian Navy ships]]
* [[List of submarines of the Indian Navy]]
* [[List of submarine classes in service]]
* [[Submarine-launched ballistic missile]]

==References==
{{Reflist}}

==External links==
{{commons category|Arihant class submarines}}
* [https://fas.org/nuke/guide/india/sub/ssn/index.html The Indian Strategic Nuclear Submarine Project by Mark Gorwitz]

{{Ship classes of the Indian Navy}}
{{SSBN classes in service}}
{{Submarines of the Indian Navy}}
{{Nuclear power in India|state=collapsed}}

{{DEFAULTSORT:Arihant-class submarine}}
[[Category:Arihant-class submarines]]
[[Category:Submarines of India]]
[[Category:Nuclear-powered submarines]]
[[Category:Submarine classes]]