William Davis was born in Wexford, Ireland on 28 July 1907, the son of William Thomas and Charlotte Eliza Davis. He joined the Royal Navy as an Engine Room Artificer Apprentice on 30 July 1923. On completion of his Apprenticeship, he served in the battleships HMS BENBOW, HMS MARLBOROUGH, the cruiser HMS SHROPSHIRE, the battleships HMS RAMILLIES and HMS VALIANT. He joined the Submarine Depot Ship HMS TITANIA on 25 April 1937. By 1 July 1938 he had been advanced to Engine Room Artificer Second Class when he was promoted to Warrant Engineer. On 12 September 1938 he was appointed to the Cruiser HMS BERWICK.

William Davis joined submarines on 26 May 1940 when he was appointed to HMS DOLPHIN ‘for the Submarine Course‘. The date of his appointment to HMS SALMON as Engineering Officer is yet to be established. On 16 July 1940, HMS SALMON was declared as presumed lost with all hands, when she failed to return from patrol in the North Sea.

William Leonard Davis is Commemorated on the Portsmouth Naval Memorial, Panel 37, Column 2.