Underwater speed record include records for submarines, autonomous underwater vehicles, and torpedoes. As these are typically for military vehicles, most are unconfirmed.
Established reports and manufacturer's claims indicate that a handful of submarines are capable of speeds exceeding . In 1960, HMS Explorer S30 achieved an underwater speed of over 30 knots. In 1965, the experimental reported a speed of . The Soviet was found in 1968 to have a speed of . In response the United States Navy developed the , with a reported speed of . The (Russian: shark)-class vessel is reportedly capable of travelling submerged at . Its predecessor, the , could attain short speed bursts of while submerged. There are also claims that the Soviet twin-propeller submarine K-222, with titanium inner and outer hulls, reached , fully submerged, during sea trials in 1969.
The British Spearfish torpedo, designed to counter high-speed Russian submarines such as the Alfa class, is reputed to reach speeds in excess of . The Russian VA-111 Shkval rocket-powered supercavitating torpedo is reportedly capable of speeds over . The German press reported on an underwater anti-torpedo missile, formerly named Barracuda, allegedly capable of reaching .