USS Sea Dog (SS-401/AGSS-401) was a Balao-class submarine in the United States Navy. She was the first ship to be named for the dogfish, a small shark of the North Atlantic, considered destructive by fishermen. Sea Dog was laid down on 1 November 1943 at the Portsmouth Navy Yard in Kittery, Maine. She was launched on 28 March 1944 sponsored by Mrs. Vernon L. Lowrance, and commissioned on 3 June 1944 with Commander Vernon L. Lowrance in command.