USS Sea Cat (SS/AGSS-399), a Balao-class submarine, was a ship of the United States Navy named for a shortened form of sea catfish, a marine fish of little food value found off the southeastern coast of the United States commissioned on 16 May 1944, with Commander Rob Roy McGregor in command.

In the autumn, it was decided to have a number of experimental changes made to the ship during her forthcoming overhaul, and she was redesignated AGSS-399 on 30 September.

After shakedown and trials off the New England coast, the new submarine departed New London, Conn., on 28 August and proceeded via the Panama Canal to Hawaii.

The submarine got underway again on 1 February 1945 for her second war patrol which she conducted in the East China Sea in a wolf pack which included Segundo (SS-398) and Razorback (SS-394).

Yard work completed on 26 July, Sea Cat sailed back to San Diego, whence she departed on 12 August for her first simulated war patrol.

In the autumn, it was decided to have a number of experimental changes made to the ship during her forthcoming overhaul, and she was redesignated AGSS-399 on 30 September.

She operated from that base for the remainder of her career, spending most of her time in the Caribbean, the Gulf of Mexico, and in waters off the southern coast of the United States.

Upon returning to Key West on 30 October, the submarine resumed her former routine and operated in Florida waters and the Caribbean until she was decommissioned on 2 December 1968 and struck from the Navy list on the same day.