The US Navy operates one of the most powerful and technologically advanced submarine fleets in the world, including Ohio-class ballistic missile submarines (SSBNs), Virginia-class attack submarines (SSNs), and Los Angeles-class attack submarines (SSNs).
Russia's Navy has both nuclear-powered and conventional submarines. Borie-class ballistic missile submarines (SSBNs), Yasen-class attack submarines (SSNs), and more.
North Korea is known to possess a relatively large number of submarines, primarily of older designs including, midnight submarines and coastal submarines
South Korea has invested in a modern submarine fleet. Types of submarines: Chang Bogo-class attack submarine (SSKs)
The Indian Navy operates several submarines, both nuclear-powered and conventional. Types of submarine: Arihant-class ballistic missile submarines (SSBNs), Scorpene- class attack submarines (SSKs) among others
Japan maintains a fleet of submarines. Types of submarines: Sōryū-class and Oyashio-class submarines.
China has been rapidly expanding its submarine fleet. Types of submarines: Jin-class ballistic missile submarines (SSBNs), Type 093 and Type 095 attack submarines (SSNs).