HMS L23 was a British L class submarine laid down on 29 August 1917 and moved to HM Dockyard, Chatham for completion. She was commissioned on an unknown date. HMS L23 survived a heavy depth charge attack by two German destroyers in February 1940. But luckily, an oil escape occurred which fooled the Germans into believing she was destroyed. L23 was decommissioned in May 1946 after a long, distinguished service.