[1] For surface running, the boats were powered by two 12-cylinder Vickers[2] 1,200-brake-horsepower (895 kW) diesel engines, each driving one propeller shaft.

[3] On the surface, the L class had a range of 3,200 nautical miles (5,900 km; 3,700 mi) at 10 knots (19 km/h; 12 mph).

[5] HMS L5 was laid down on 23 August 1916 by Swan Hunter at their Wallsend shipyard, launched on 1 September 1917, and completed on 15 May 1918.

L5 was assigned to the 4th Submarine Flotilla and HMS Titania in 1919 and sailed to Hong Kong, arriving on 14 April 1920.

On 20 October 1927 off Hong Kong, L5 and HMS L4 rescued the crew of the merchant ship SS Irene from a pirate attack after firing her deck gun.