USS S-31 (SS-136) was a first-group (S-1 or "Holland") S-class submarine of the United States Navy. Her keel was laid down on 13 April 1918 by the Union Iron Works in San Francisco, California. She was launched on 28 December 1918 sponsored by Mrs. George A. Walker, and commissioned on 11 May 1922 with Lieutenant William A. Heard in command.