HMS E43 was a British E class submarine built by Swan Hunter, Wallsend. She was laid down on 22 December 1914 and was commissioned on 20 February 1916. On 19 January 1917 E43 collided with E36 off Harwich in the North Sea; E36 sank with all hands. E43 was sold on 3 January 1921 but became stranded under tow west of St Agnes Head, Cornwall on 25 November 1921.