HMS D1 was a British D class submarine built by Vickers, Barrow. D1 was laid down on 14 May 1907 and was launched on 16 May 1908 at Barrow. She was commissioned in September 1909. In 1910, D1 took part in the Annual Manoevures. She torpedoed 2 blue fleet cruisers off Colonsay. This showed that the D class could operate a considerable away from their base at Fort Blockhouse. D1 was sunk as a target on 23 October 1918.