A Balao-class submarine, USS Lionfish was laid down on 15 December 1942, launched on 7 November 1943, and commissioned on 1 November 1944. Her first captain was Lt. Cdr. Edward D. Spruance, son of the famous World War II admiral, Raymond Spruance.
After completing her shakedown cruise off New England, she headed to the Pacific and commenced her first war patrol in Japanese waters on 1 April 1945. Ten days later, she dodged two torpedoes fired at her by a Japanese submarine and on 1 May destroyed a Japanese schooner with her deck guns. After a rendezvous with the submarine Ray, she transported B-29 survivors to Saipan and then made her way to Midway Island for replenishment.
On 2 June she started her second war patrol, and on 10 July she fired torpedoes at a surfaced Japanese submarine, after which Lionfish's crew heard explosions and observed smoke through their periscope. She subsequently fired on two more Japanese submarines and ended her second and last war patrol performing lifeguard duty (the rescue of downed fliers) off the coast of Japan.
When hostilities ended on 15 August she headed for San Francisco and was decommissioned at Mare Island Navy Yard on 16 January 1946.
Lionfish was recommissioned on 31 January 1951, and headed for the East Coast for training cruises. After participating in NATO exercises and a Mediterranean cruise, she returned to the East Coast and was decommissioned at the Boston Navy Yard on 15 December 1953.
In 1960, this venerable submarine was called to duty again, this time serving as a reserve training submarine at Providence, Rhode Island. In 1971, she was stricken from the Navy Register, and in 1973, she was unveiled for permanent display as a memorial at Battleship Cove, where she has evolved into one of the museum's most popular exhibits and a revered monument to all submariners.