HMS H12
 HMS H12 was a British H-class submarine built by Fore River Yard Quincy Massachusetts. She was laid down on an unknown date and commissioned in 1915.HMS H12 along with HMS H11 and HMS H13 to HMS H20 were all built in America but were interned by the United States government until the USA entered World War I.HMS H12 was sold in April 1920 in Dover.