HMS L55 was a British L class submarine built by Fairfield Shipbuilding and Engineering Company, Govan, Clyde. She was laid down on 21 September 1917 and was commissioned on 19 December 1918. In 1919 L55 was sunk in the Baltic Sea by Bolshevik vessels while serving as part of the Allied intervention in the Russian Civil War. The submarine was raised in 1928 and repaired by the Soviets. After being used for training, she finally was scrapped in the 1950s.