View source for Attack submarine

{{See also|Coastal submarine|Midget submarine}}
{{short description|Submarine designed to destroy other ships}}
[[File:HMCS Windsor SSK 877.jpg|thumb|300px|[[HMCS Windsor|HMCS ''Windsor'']], an attack submarine of the [[Royal Canadian Navy]]]]

An '''attack submarine''' or '''hunter-killer submarine''' is a [[submarine]] specifically designed for the purpose of attacking and sinking other submarines, [[surface combatant]]s, and [[merchant vessel]]s. In the [[Soviet Navy|Soviet]] and [[Russian Navy|Russian]] navies they were and are called "multi-purpose submarines".{{sfnp|Gorshkov|1979|page= 55}} They are also used to protect friendly surface combatants and [[Ballistic missile submarine|missile submarines]].<ref>{{cite web
  |publisher=US Navy
  |title=Attack Submarine Info
  |url=http://navysite.de/submarine.htm
  |access-date=August 17, 2012
}}</ref> Some attack subs are also armed with [[submarine-launched cruise missile|cruise missile]]s, increasing the scope of their potential missions to include land targets.

Attack submarines may be either [[nuclear marine propulsion|nuclear-powered]] or diesel–electric ("conventionally") powered. In the U.S. Navy [[hull classification symbol|naming system]], and in the equivalent NATO system (STANAG 1166), nuclear-powered attack submarines are known as [[SSN (hull classification symbol)|SSNs]] and their [[anti-submarine warfare|anti-submarine (ASW)]] diesel–electric predecessors are [[SSK (hull classification symbol)|SSKs]]. In the U.S. Navy, SSNs are unofficially called "fast attacks".<ref>{{Citation |title=Appendix:Glossary of U.S. Navy slang |date=2024-10-24 |work=Wiktionary, the free dictionary |url=https://en.wiktionary.org/wiki/Appendix:Glossary_of_U.S._Navy_slang#:~:text=SSN |access-date=2024-10-26 |language=en}}</ref>

==History==
===Origins===
During [[World War II]], submarines that fulfilled the offensive surface attack role were termed [[fleet submarine]]s in the U.S. Navy and "ocean-going", "long-patrol", "type 1" or "1st class" by continental European navies.{{sfnp|Friedman|1995| pages = 99–104 }}{{sfn|le Masson|1969|p=143}}

In the [[action of 9 February 1945]], {{HMS|Venturer|P68|6}} sank {{GS|U-864||2}} while both were at [[periscope depth]]. This was the first and so far only intentional sinking of a submerged submarine by another submerged submarine. ''U-864'' was snorkeling, thus producing much noise for ''Venturer''{{'}}s [[hydrophone]]s (an early form of passive [[sonar]]) to detect, and ''Venturer'' was fortunate in having over 45 minutes to plot the [[U-boat]]'s zig-zag course by observing the snorkel mast. ''Venturer''{{'}}s commander, [[Jimmy Launders|James S. "Jimmy" Launders]], was astute in assuming the U-boat would execute an "[[Crash dive|emergency deep]]" maneuver once it heard the torpedoes in the water, thus the "spread" of four torpedoes immediately available was aimed on that assumption. One hit, sinking the U-boat.{{sfn|Jones|1986|p=197}}{{sfn|Preisler|Sewell|2013|pp=7, 16, 164–167, 183}}

====Beginnings of the attack submarine type====

Following World War II, advanced German submarines, especially the [[Type XXI submarine|Type XXI U-boat]], became available to the Allies, particularly the U.S. Navy and the Soviet Navy. Initially, the [[German Type XVII submarine|Type XVII U-boat]], with a Walter [[hydrogen peroxide]]-fueled [[gas turbine]] allowing high sustained underwater speed, was thought to be more developed than was actually the case, and was viewed as the submarine technology of the immediate future. However, the Type XXI, streamlined and with a high battery capacity for high submerged speed, was fully developed and became the basis for most non-nuclear submarine designs worldwide through the 1950s.{{sfnp|Friedman|1994| pages = 75–85 }} In the U.S. Navy, the [[Greater Underwater Propulsion Power Program]] (GUPPY) was developed to modernize World War II submarines along the lines of the Type XXI.<ref>[https://web.archive.org/web/20000819012150/http://guppysubmarinetribute.homestead.com/Tribute.html GUPPY and other diesel boat conversions page]</ref> By 1955 the U.S. Navy was using the term 'attack submarine' to describe the GUPPY conversions and the first postwar submarines (the {{sclass|Tang|submarine|4}} and the {{USS|Darter|SS-576|2}}).{{sfnp|Friedman|1994| page = 64 }}

====Beginnings of a separate hunter-killer submarine type (SSK)====

It was realized that the [[Soviet Union]] had acquired Type XXI and other advanced U-boats and would soon be putting their own equivalents into production. In 1948 the U.S. Navy prepared estimates of the number of [[anti-submarine warfare]] (ASW)-capable submarines that would be needed to counter the hundreds of advanced Soviet submarines that were expected to be in service by 1960. Two scenarios were considered: a reasonable scenario assuming the Soviets would build to their existing force level of about 360 submarines, and a "nightmare" scenario projecting that the Soviets could build submarines as fast as the Germans had built U-boats, with a force level of 2,000 submarines. The projected U.S. [[SSK (hull classification symbol)|SSK]] force levels for these scenarios were 250 for the former and 970 for the latter. Additional anti-surface (i.e., 'attack'), [[Cruise missile submarine#U.S. Navy|guided missile]], and [[Radar picket#Converted and purpose-built submarines|radar picket]] submarines would also be needed. By comparison, the total U.S. submarine force at the end of World War II, excluding obsolescent training submarines, was just over 200 boats.{{sfnp|Friedman|1994| pages = 75–85 }}

[[File:USS Bonita (SSK-3).jpg|thumb|[[USS Bonita (SSK-3)|USS ''K-3'']] with BQR-4 sonar dome]]
A small submarine suitable for mass production was designed to meet the SSK requirement. This resulted in the three submarines of the [[United States K-1-class submarine (1951)|''K-1'' class]] (later named the ''Barracuda'' class), which entered service in 1951. At {{convert|750|long ton|t|lk=on}} surfaced, they were considerably smaller than the {{convert|1650|long ton|t|lk=on}} boats produced in World War II. They were equipped with an advanced passive sonar, the bow-mounted BQR-4, but had only four [[torpedo tube]]s. Initially, a sonar located around the conning tower was considered, but tests showed that bow-mounted sonar was much less affected by the submarine's own noise.

While developing the purpose-built SSKs, consideration was given to converting World War II submarines into SSKs. The less-capable {{Sclass|Gato|submarine|4}} was chosen for this, as some of the deeper-diving {{Sclass|Balao|submarine|5}}- and {{Sclass|Tench|submarine|0}} boats were being upgraded as GUPPYs. [[Gato-class submarine#Hunter-killer|Seven ''Gato''-class boats]] were converted to SSKs in 1951–53. These had the bow-mounted BQR-4 sonar of the other SSKs, with four of the six bow torpedo tubes removed to make room for the sonar and its electronics. The four stern torpedo tubes were retained. Two diesel engines were removed, and the auxiliary machinery was relocated in their place and sound-isolated to reduce the submarine's own noise.{{sfnp|Friedman|1994| pages = 75–85 }}<ref>[https://web.archive.org/web/20010125055900/http://guppysubmarinetribute.homestead.com/SSK.html List of USN SSKs]</ref>

The Soviets took longer than anticipated to start producing new submarines in quantity. By 1952 only ten had entered service.<ref>{{Cite web |url=http://russian-ships.info/eng/submarines/index_convent.htm |title=Russian ships website in English, conventional submarines page |access-date=2014-12-12 |archive-url=https://web.archive.org/web/20141022083346/http://russian-ships.info/eng/submarines/index_convent.htm |archive-date=2014-10-22 |url-status=dead }}</ref> However, production was soon ramped up. By the end of 1960 a total of 320 new Soviet submarines had been built (very close to the USN's 1948 low-end assumption), 215 of them were the [[Whiskey-class submarine|Project 613 class]] (NATO Whiskey class), a smaller derivative of the Type XXI. Significantly, eight of the new submarines were nuclear-powered.<ref name="russian-ships.info">{{Cite web |url=http://russian-ships.info/eng/submarines/index_nuclear.htm |title=Russian ships website in English, nuclear submarines page |access-date=2014-12-12 |archive-url=https://web.archive.org/web/20150102200616/http://russian-ships.info/eng/submarines/index_nuclear.htm |archive-date=2015-01-02 |url-status=dead }}</ref>{{sfnp|Gardiner|Chumbley|1995| pages=396–401 }}

===Nuclear era===
====End of the U.S. conventional hunter-killers (SSK)====
{{USS|Nautilus|SSN-571|6}}, the world's first [[nuclear submarine]], was operational in 1955; the Soviets followed this only three years later with their first [[November-class submarine|Project 627 "Kit"-class SSN]] (NATO November class). Since a nuclear submarine could maintain a high speed at a deep depth indefinitely, conventional SSKs would be useless against them:

{{blockquote|By the fall of 1957, ''Nautilus'' had been exposed to 5,000 dummy attacks in U.S. exercises. A conservative estimate would have had a conventional submarine killed 300 times: ''Nautilus'' was ruled as killed only 3 times...Using their active sonars, nuclear submarines could hold contact on diesel craft without risking counterattack...In effect, ''Nautilus'' wiped out the ASW progress of the past decade.{{sfnp|Friedman|1994|page=109}}}}

As the development and deployment of nuclear submarines proceeded, in 1957–59 the U.S. Navy's SSKs were decommissioned or redesignated and reassigned to other duties. It had become apparent that all nuclear submarines would have to perform ASW missions.

====Other new technologies====

[[File:USS Thresher underway April 1961.jpg|thumb|{{USS|Thresher|SSN-593|6}}, the first high-speed deep-diving SSN optimized for both ASW and surface attack]] Research proceeded rapidly to maximize the potential of the nuclear submarine for the ASW and other missions. The U.S. Navy developed a fully streamlined hull form and tested other technologies with the conventional {{USS|Albacore|AGSS-569|6}}, commissioned in 1953. The new hull form was first operationalized with the three conventional {{Sclass|Barbel|submarine|0}} boats and the six nuclear {{Sclass|Skipjack|submarine|0}} boats, when both classes entered service beginning in 1959. Both classes used the BQS-4 and BQR-2 bow mounted sonars.{{sfnp|Friedman|1994|pages=31–35, 242}}{{sfnp|Gardiner|Chumbley|1995|pages=605–606}} The {{USS|Skipjack|SSN-585|2}} was declared the "world's fastest submarine" following trials, although the actual speed was kept secret.

Sonar research showed that a sonar sphere capable of three-dimensional operation, mounted at the very bow of a streamlined submarine, would increase detection performance. This was recommended by [[Project Nobska]], a 1956 study ordered by [[Chief of Naval Operations]] Admiral [[Arleigh Burke]].{{sfnp|Friedman|1994| pages = 109–113 }} The one-off {{USS|Tullibee|SSN-597|2}} in 1960 and the {{Sclass|Thresher|submarine|4}} starting in 1961 were the first with a bow-mounted sonar sphere, the BQQ-2; midships torpedo tubes angled outboard were fitted to make room for the sphere.{{sfnp|Friedman|1994| pages = 75–85 }}<ref>[http://www.navy.mil/navydata/cno/n87/history/tech-3.html US Navy Submarine Warfare Division, ''Technical Innovations of the Submarine Force'', retrieved 14 December 2014] {{webarchive |url=https://web.archive.org/web/20141216165950/http://www.navy.mil/navydata/cno/n87/history/tech-3.html |date=December 16, 2014 }}</ref>

====Failure to develop a U.S. nuclear hunter-killer (SSKN)====
''Tullibee'' was a type of nuclear-powered SSK; technologically very successful, intentionally slow but ultra-quiet with [[turbine–electric powertrain|turbo–electric drive]]. Her unexpectedly high cost compared with the ''Thresher'' proved it was impossible to build a low-cost nuclear SSK (several [[nuclear reactor]] features could not be scaled down beyond a certain point, including [[Radiation protection#Radiation protection|radiation shielding]]). This result coupled with her lower performance was judged to be not [[Cost-effectiveness analysis|cost-effective]] and the type was not repeated; the Navy decided to merge the hunter-killer role with the attack submarines, making the terms interchangeable.{{sfnp|Friedman|1994| pages = 134–138 }} ''Thresher'' was faster and had an increased diving depth, carried twice as many torpedoes, included comparable sound silencing improvements, and was commissioned only nine months later.{{sfnp|Friedman|1994| pages = 235, 243 }}

''Thresher'''s loss in April 1963 triggered a major redesign of subsequent U.S. submarines known as the [[SUBSAFE]] program.{{sfnp|Gardiner|Chumbley|1995| pages=605–606 }} However, ''Thresher''{{'}}s general arrangement and concept were continued in all subsequent U.S. Navy attack submarines.

====Later developments====
Britain commissioned its first nuclear attack submarine {{HMS|Dreadnought|S101|6}} in 1963 with a U.S. [[S5W reactor]]. At the same time as the ''Dreadnought'' construction, attempts were made to transfer U.S. reactor technology to Canada and the Netherlands. Admiral [[Hyman G. Rickover]] considered such technology to be obvious, but a visit to the Soviet nuclear icebreaker {{ship||Lenin|1957 icebreaker|2}} reportedly "appalled him" and convinced him that he should cancel the transfers to retain secrets.{{sfnp|Gardiner|Chumbley|1995| page=529}}{{sfnp|Friedman|1994|page=127}}

The first fully streamlined Soviet attack submarines were the [[Victor-class submarine|Project 671 "Yorsh" class]] (NATO Victor I class), which first entered service in 1967.<ref name="russian-ships.info"/>{{sfnp|Gardiner|Chumbley|1995| pages=403–406 }}

China commissioned its first nuclear attack submarine {{ship|Chinese submarine|Changzheng 1||2}} (NATO Han class) in 1974, and France its first {{sclass|Rubis|submarine|1}} in 1983.<ref name="5F3P8GRF00011232">{{Cite web|date=2009-08-03|title=深海蓝鲨—中国海军091，093型攻击核潜艇_网易新闻中心|url=http://war.news.163.com/09/0725/22/5F3P8GRF00011232.html|access-date=2021-04-19|archive-url=https://web.archive.org/web/20090803154829/http://war.news.163.com/09/0725/22/5F3P8GRF00011232.html|archive-date=3 August 2009}}</ref><ref>{{in lang|fr}} [http://www.lemarin.fr/secteurs-activites/defense/26230-deconstruction-le-sna-rubis-attendu-debut-2017-cherbourg Déconstruction : le SNA « Rubis » attendu début 2017 à Cherbourg], le marin.fr</ref>

The only time in history that a nuclear attack submarine engaged and sank an enemy warship was in the [[Falklands War]], when on 2 May 1982 the [[United Kingdom|British]] nuclear submarine {{HMS| Conqueror|S48|6}} torpedoed and sank the [[Argentina|Argentine]] light cruiser {{ship|ARA|General Belgrano}}.{{sfnp|Rossiter|2009|pages=305–318, 367–377}}

The U.S. Navy commissioned the first [[Seawolf-class submarine|''Seawolf'']] and [[Virginia-class submarine|''Virginia''-class]] nuclear powered submarines in 1997 and 2004 respectively.

As of 2025 Brazil has a nuclear attack submarine [[Brazilian submarine Álvaro Alberto|under construction]],<ref name="Prosub Naval">{{cite news |title=O Prosub e o submarino nuclear brasileiro SN-BR|url=https://www.naval.com.br/blog/2018/02/20/o-prosub-e-o-submarino-nuclear-brasileiro-sn-br|publisher=Poder Naval|language=pt|date=20 February 2018}}</ref> India has [[Project 75 Alpha|finalized a nuclear attack submarine interim design]],{{sfn|Pubby|2020}}{{sfn|Gupta|2021}} and Australia has started a nuclear attack submarine program under the [[AUKUS]] security pact with UK and US assistance.<ref name="Pursuenuclear">{{cite press release |author1=Prime Minister |author2=Minister for Defence |author3=Minister for Foreign Affairs |author4=Minister for Women |title=Australia to pursue Nuclear-powered Submarines through new Trilateral Enhanced Security Partnership |url=https://www.pm.gov.au/media/australia-pursue-nuclear-powered-submarines-through-new-trilateral-enhanced-security |website=Prime Minister of Australia |access-date=25 September 2021 |date=16 September 2021 |archive-url=https://web.archive.org/web/20210927191633/https://www.pm.gov.au/media/australia-pursue-nuclear-powered-submarines-through-new-trilateral-enhanced-security |archive-date=27 September 2021 |url-status=live }}[[File:CC-BY_icon.svg|50x50px]] This article contains quotations from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International Licence]].</ref>

===Modern conventional submarines===
[[File:HMS Gotland with USS Ronald Reagan.jpg|thumb|{{HSwMS|Gotland|Gtd|6}} with {{USS|Ronald Reagan}}]]
[[File:DRDO AIP (Air Independent Propulsion) model for Kalvari-class submarine.jpg|thumb|right|The [[Air-independent propulsion]] module of the [[Kalvari-class submarine (2015)|Kalvari class]] submarines]]
Conventional attack submarines have however remained relevant throughout the nuclear era, with the British {{Sclass|Oberon|submarine|5}} class and the Soviet {{sclass2|Romeo|submarine|5}}, {{sclass2|Foxtrot|submarine|5}}, {{sclass2|Tango|submarine|5}} and {{sclass2|Kilo|submarine|5}} classes being good examples which served during the [[Cold War]]. 

With the advent of [[air-independent propulsion]] technology, these submarines have grown more and more capable. Examples include the [[Type 212 submarine|Type 212]], {{sclass2|Scorpène|submarine|5}} and {{Sclass|Gotland|submarine|5}} classes of submarine. The U.S. Navy [[lease]]d {{HSwMS|Gotland|Gtd|6}} to perform the opposing force role during [[Anti-submarine warfare|ASW]] exercises tactics.<ref>{{Cite web|url=https://www.naval-technology.com/projects/gotland/|title=SSK Gotland Class (Type A19)|website=Naval Technology|language=en-GB|access-date=2020-03-15}}</ref> The ''Gotland'' caused a stir in 2005 when during training it "sank" the American carrier {{USS|Ronald Reagan}}.{{sfn|Roblin|2016}}<ref>{{Cite web|url=https://www.popularmechanics.com/military/navy-ships/a19784775/gotland-class-sub-ronald-reagan-war-games/|title=How a Plucky Swedish Sub Took Out a US Carrier All on Its Own|date=2018-04-13|website=Popular Mechanics|language=en-US|access-date=2020-03-15}}</ref>

==Operators==
{{unreferenced section|date=July 2022}}

===Current operators===
* {{navy|Algeria}} operates six {{sclass2|Kilo|submarine|2}}s.
* {{navy|Argentina}} operates one [[Type 209 submarine]] as a pier-side trainer; one {{sclass2|TR-1700|submarine|2}} remains in inventory but is inactive.
* {{navy|Australia}} operates six {{sclass|Collins|submarine|2}}s.
* {{navy|Bangladesh}} operates two [[Type 035 submarine|Ming-class submarines]].
* {{navy|Brazil}} operates five [[Type 209 submarine]]s and three {{sclass2|Riachuelo|submarine|2}}s.
* {{navy|Canada}} operates four {{sclass|Victoria|submarine|2}}s.
* {{navy|Chile}} operates two [[Type 209 submarine]]s and two {{sclass2|Scorpène|submarine|2}}s.
* {{navy|China}} operates six [[Type 093 submarine|Shang-class submarines]], three [[Type 091 submarine|Han-class submarines]], seventeen [[Type 039A submarine|Yuan-class submarines]], thirteen [[Type 039 submarine|Song-class submarines]], twelve {{sclass2|Kilo|submarine|2}}s, and four [[Type 035 submarine|Ming-class submarines]].
* {{navy|Taiwan}} operates two {{sclass|Zwaardvis|submarine|2}}s, one {{sclass|Tench|submarine|2}} and one {{sclass|Balao|submarine|2}}.
* {{navy|Colombia}} operates two [[Type 209 submarine]]s and two [[Type 206 submarine]]s.
* {{navy|Ecuador}} operates two [[Type 209 submarine]]s.
* {{navy|Egypt}} operates four [[Type 209 submarine]]s and four {{sclass2|Romeo|submarine|2}}s.
* {{navy|France}} operates two {{sclass|Rubis|submarine|2}}s and three {{sclass2|Barracuda|submarine|2||France}}s.
* {{navy|Germany}} operates six [[Type 212 submarine]]s.
* {{navy|Greece}} operates six [[Type 209 submarine]]s and four [[Type 214 submarine]]s.
* {{navy|India}} operates four [[Type 209 submarine]]s, six {{sclass2|Scorpène|submarine|2}}<nowiki/>s, and seven {{sclass2|Sindhughosh|submarine|2}}<nowiki/>s.
* {{navy|Indonesia}} operates three {{sclass|Nagapasa|submarine|2}}s and one {{sclass|Cakra|submarine|2}}.
* {{navy|Iran}} operates three {{sclass2|Kilo|submarine|2}}s.
* {{navy|Israel}} operates five {{sclass|Dolphin|submarine|2}}s, with a sixth on sea trials as of late 2024.
* {{navy|Italy}} operates four {{sclass|Sauro|submarine|2}}s and four [[Type 212 submarine]]s.
* {{navy|Japan}} operates nine {{sclass|Oyashio|submarine|2}}s, twelve {{sclass|Sōryū|submarine|2}}s, and three {{sclass|Taigei|submarine|2}}s.{{sfn|Vavasseur|2023}}
* {{navy|North Korea}} operates twenty {{sclass2|Romeo|submarine|2}}s.{{cn|date=July 2022}}
* {{navy|South Korea}} operates nine {{sclass|Jang Bogo|submarine|2}}s, nine [[Type 214 submarine]]s, and two [[KSS-III submarine]]s.
* {{navy|Malaysia}} operates two {{sclass2|Scorpène|submarine|2}}s.
* {{navy|Myanmar}} operates a single {{sclass2|Kilo|submarine|2}}, gifted by India,{{sfn|Sharma|Nitta|2020}} and a single [[Type 035 submarine|''Ming''-class submarine]], purchased from China.
* {{navy|Netherlands}} operates three {{sclass|Walrus|submarine|2}}s.
* {{navy|Norway}} operates six {{sclass|Ula|submarine|2}}s.
* {{navy|Pakistan}} operates five {{sclass|Agosta|submarine|2}}s.
* {{navy|Peru}} operates six [[Type 209 submarine]]s.
* {{navy|Poland}} operates one {{sclass2|Kilo|submarine|2}}.
* {{navy|Portugal}} operates two [[Type 214 submarine]]s.
* {{navy|Romania}} possesses a single {{sclass2|Kilo|submarine|2}}, though it is not operational.
* {{navy|Russia}} operates ten {{sclass|Akula|submarine|2}}s, two {{sclass2|Victor III|submarine|2}}s, two {{sclass2|Sierra|submarine|2}}s, and c. twenty-one {{sclass2|Kilo|submarine|2}}s (of which nine are the "Improved Kilo" variant).
* {{navy|Singapore}} operates two {{sclass|Sjöormen|submarine|2}}s and two {{sclass|Västergötland|submarine|2}}s, all purchased from Sweden.
* {{navy|South Africa}} operates three [[Type 209 submarine]]s.
* {{navy|Spain}} operates one {{sclass|Agosta|submarine|2}} and one {{sclass|S-80 Plus|submarine|2}} as of late 2024.
* {{navy|Sweden}} operates three {{sclass|Gotland|submarine|2}}s and one {{sclass|Södermanland|submarine|2}}.
* {{navy|Turkey}} operates twelve [[Type 209 submarine]]s.
* {{navy|UK}} operates five {{sclass|Astute|submarine|2}}s as of late 2024.
* {{naval|USA}} operates twenty-three {{sclass|Los Angeles|submarine|2}}s, three {{sclass|Seawolf|submarine|2}}s, and twenty-four {{sclass|Virginia|submarine|2}}s.
* {{navy|Venezuela}} operates two [[Type 209 submarine]]s.
* {{navy|Vietnam}} operates six {{sclass2|Kilo|submarine|2}}s.

===Former operators===

* {{navy|Albania}} retired all four of its {{sclass2|Whiskey|submarine|2}}s in 1989.
* {{navy|Bulgaria}} decommissioned its last {{sclass2|Romeo|submarine|2}}, ''Slava'' in 2011.
* {{navy|Cuba}} retired all three of its {{sclass2|Foxtrot|submarine|2}}s in the 1990s.
* {{navy|Denmark}} retired its last two {{sclass|Kobben|submarine|2}}s and its lone {{sclass|Näcken|submarine|2}} in 2005.
* {{navy|Libya}} retired its six {{sclass2|Foxtrot|submarine|2}}s from active service in 1984.
* {{navy|Montenegro}} decommissioned its last {{sclass|Heroj|submarine|2}} in 2006.
* {{navy|Serbia and Montenegro}} transferred its entire navy to [[Montenegro]] upon their independence in 2006.
* {{navy|Syria}} retired all three of its {{sclass2|Whiskey|submarine|2}}s in 1993.
* {{navy|Ukraine}} only submarine, {{ship|Ukrainian submarine|Zaporizhzhia||2}}, was captured by the Russian Navy during the [[Annexation of Crimea by the Russian Federation|2014 Annexation of Crimea]].

===Former operators (pre-modern attack)===

* {{navy|Austria-Hungary}} lost its entire fleet following the Empire's collapse after World War I.
* {{navy|Estonia}} two {{sclass|Kalev|submarine|2}}s were seized by the Soviet Union in 1940. After Estonia regained independence in 1991, it took back {{ship|EML|Lembit}}, and was kept in ceremonial commission as the flagship until 2011.
* {{navy|Finland}} forced to decommission all five of its submarines following World War II under the [[Paris Peace Treaty]].
* {{navy|Latvia}} two {{sclass|Ronis|submarine|2}}s were seized by the Soviet Union in 1940.
* {{navy|Thailand}} decommissioned its last {{sclass|Matchanu|submarine|2}} in 1951.

==See also==
* [[List of submarine classes in service]]
* [[List of submarine operators]]
* {{annotated link|Nuclear navy}}
* {{annotated link|Coastal submarine}}
* {{annotated link|History of submarines}}

== References ==
=== Citations ===
{{Reflist}}

=== Sources ===
{{refbegin}}
* {{cite book 
  | title = U.S. Submarines Through 1945: An Illustrated Design History 
  | last = Friedman | first = Norman |author-link = Norman Friedman
  | publisher = [[United States Naval Institute]]
  | year = 1995
  | location = [[Annapolis, Maryland]]
  | isbn = 1-55750-263-3
 }}
* {{cite book
  |title = U.S. Submarines Since 1945: An Illustrated Design History
  |last = Friedman  |first = Norman
  |publisher = United States Naval Institute
  |year = 1994
  |location = Annapolis, Maryland
  |isbn = 1-55750-260-9 
}}
* {{Cite book
  |title=Conway's All the World's Fighting Ships 1947–1995
  |last1=Gardiner  |first1=Robert 
  |last2=Chumbley  |first2=Stephen
  |publisher=Conway Maritime Press
  |year=1995
  |isbn=1-55750-132-7
}}
* {{Cite book
  |title=The Sea Power of the State
  |last=Gorshkov  |first=Sergei Georgievich
  |edition=2nd 
  |publisher=Naval Institute Press
  |year=1979
  |isbn=0-87021-961-8
}}
* {{Cite news
  |last=Gupta |first=Shishir
  |title=For Navy, 6 nuclear-powered submarines take priority over 3rd aircraft carrier
  |newspaper=The Hindustan Times
  |date=2021-03-24
  |url=https://www.hindustantimes.com/india-news/for-navy-6-nuclear-powered-submarines-take-priority-over-3rd-aircraft-carrier-101616564522467.html
  |access-date=2021-04-02
}}
* {{cite book
  |title=Submarines versus U-Boats
  |last=Jones |first=G. P.
  |publisher=William Kimber
  |year=1986
  |location=London
  |isbn=978-0-7183-0626-7
}}
* {{cite book
  |last=le Masson |first=Henri
  |title =Navies of the Second World War |volume =The French Navy 1 
  |publisher =Doubleday & Company
  |date =1969
  |location =Garden City, New York 
}}
* {{cite book
  |title=Code-Name Caesar: The Secret Hunt for U-boat 864 during World War II
  |last1=Preisler |first1=J.
  |last2=Sewell |first2=K.
  |publisher=Berkley Books
  |year=2013 |orig-year=2012
  |location=New York |edition=repr. Souvenir Press, London
  |isbn=978-0-285-64203-4
}}
* {{Cite news
  |last=Pubby |first=Manu
  |title=India's Rs 1.2 lakh crore nuclear submarine project closer to realisation
  |work=The Economic Times
  |date=2020-02-21
  |url=https://economictimes.indiatimes.com/news/defence/indias-rs-1-2-l-cr-n-submarine-project-closer-to-realisation/articleshow/74234776.cms |access-date=2020-02-23
}}
* {{Cite web
  |last=Roblin |first=Sebastien
  |title=Sweden's Super Stealth Submarines Are So Lethal They 'Sank' a U.S. Aircraft Carrier
  |website=The National Interest |date=2016-11-13 |language=en
  |url=https://nationalinterest.org/blog/the-buzz/swedens-super-stealth-submarines-are-so-lethal-they-sank-us-18383
  |access-date=2020-03-15
}}
* {{Cite book
  |title=Sink the Belgrano
  |last=Rossiter|first=Mike
  |publisher=Random House
  |year=2009
  |location=London
  |isbn=978-1-4070-3411-9|oclc=1004977305
}}
* {{Cite web
  |last1=Sharma |first1=Kiran
  |last2=Nitta |first2=Yuichi 
  |title=With an eye on China, India gifts submarine to Myanmar 
  |website=Nikkei Asia |date=22 October 2020 |language=en-GB
  |url=https://asia.nikkei.com/Politics/International-relations/With-an-eye-on-China-India-gifts-submarine-to-Myanmar
  |access-date=2023-07-27
}}
* {{cite web
  |last=Vavasseur |first=Xavier
  |title=Japan Commissions 'Hakugei' 「はくげい」2nd Taigei Class Submarine 
  |website=Naval News
  |date=20 March 2023
  |url=https://www.navalnews.com/naval-news/2023/03/japan-commissions-hakugei-%e3%80%8c%e3%81%af%e3%81%8f%e3%81%92%e3%81%84%e3%80%8d2nd-taigei-class-submarine
  |access-date=20 March 2023
}}
* {{DANFS}}
{{refend}}

== External links ==
* {{Commons category-inline|Attack submarines}}

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{{Current SSN}}
{{Warship types of the 19th & 20th centuries}}

[[Category:Attack submarines| ]]
[[Category:Ship types]]