USS H-8

The USS H-8 (SS-31) was a H-class submarine of the United States Navy. She was the third ship of the United States Navy to be named with the "H" designation.

Laid down on 28 January 1911 by Union Iron Works of San Francisco, California, she was launched on 4 May 1918 and commissioned on 10 October 1918 with Lieutenant J.H. Ewen in command.

After commissioning, USS H-8 operated along the Pacific coast, conducting training exercises and patrols. Due to the Armistice ending World War I just a month after her commissioning, she never saw active combat service.

Following a brief period of service, USS H-8 was decommissioned on 17 July 1922 and struck from the Naval Vessel Register on 26 February 1931. She was sold for scrapping on 28 November 1931. Her short career was typical for many submarines commissioned late in World War I, as postwar naval reductions led to the decommissioning of numerous ships.