The following countries operate or have operated submarines for naval or other military purposes.

• Algeria^[1]
• Australia
• Azerbaijan
• Bangladesh
• Brazil^[2]
• Canada
• Chile^[3]
• Colombia^[4]
• Cuba - One indigenous design submarine was reported in service in 2020.^[5]
• Ecuador^[6]
• Egypt^[7]
• France (list)
• Germany (list)
• Greece
• India (list)
• Indonesia
• Iran
• Italy (list)
• Israel
• Japan
• Malaysia
• Myanmar
• Netherlands (list)^[8]
• North Korea
• Norway
• Pakistan
• People's Republic of China
• Republic of China (Taiwan)
• Peru^[9]
• Poland
• Portugal (list)^[10]
• Russia (list) (some ex-Soviet Union)
• Singapore
• South Africa
• South Korea
• Spain (list)^[11]
• Sweden (list)
• Turkey (list)
• United Kingdom (list)
• United States (list)
• Venezuela^[12]
• Vietnam

Ballistic missile submarines are larger than any other type of submarine, in order to accommodate ballistic missiles capable of carrying nuclear warheads.

• China – Type 094 submarine, Type 092 submarine
• France – Triomphant class
• India – Arihant-class submarine
• Russia – Delta and Borei classes
• United Kingdom – Vanguard class
• United States – Ohio class

• Albania - all retired 1998
• Argentina - Two submarines inactive (non-operational) in the Argentinian Navy.^[13][14]
• Austria-Hungary (list)
• Bulgaria - all retired by 2011
• Cuba - Operated 3 Foxtrot-class submarines retired.
• Denmark^[15] - retired after 2003
• Estonia (Kalev and Lembit) - decommissioned 1955 in the Soviet Navy
• Finland - last subs decommissioned after World War II
• Latvia - all submarines taken over by Soviet Union in 1940.
• Libya - all Foxtrot-class submarines retired (1 non-commissioned remains docked)
• Romania (Delfinul, not operational; used for dockside training)^[16][17]
• Serbia and Montenegro (ex-Socialist Federal Republic of Yugoslavia) ^[18]
• Soviet Union (list) (prior to 1991 collapse, many now operated by successor state Russia)
• Syria - all Romeo-class submarines retired around 1992
• Thailand (Matchanu class during the Franco-Thai War - built in Japan 1938 and retired 1951)
• Ukraine (Zaporizhzhia - lost to Russia in the 2014 Crimean crisis)^[19]

• List of submarine classes