HMS D7 was a British D class submarine built by Chatham Dockyard. D7 was laid down on 14 February 1910, launched 14 January 1911 and was commissioned on 14 December 1911. D7 torpedoed U-45 on the surface with a single shot from 800 yards off the North coast of Ireland on 12 September 1917. The torpedo was launched from the stern torpedo tube. Then on the 10 February 1918, D7 was mistakenly depth charged by HMS Pelican but she survived. D7 collided with a U boat in May 1918. Her periscopes were damaged but she escaped otherwise unscathed. D7 was sold on 19 December 1921 to H. Pounds.