Gnat saw service during the First World War as part of a flotilla operating on the Tigris and Euphrates rivers.

In 1927 Gnat participated as part of a Royal Navy flotilla in the Nanking Incident, helping to protect British and other international citizens and business interests in China.

[1] During the Second World War, Gnat was part of the China Station until 1940, when she was relieved by HMS Grasshopper.

Along with Stuart, Vampire, Voyager and Terror, she supported the 6th Australian Division's assault on Tobruk on 21 January 1941 with the port being secured the following day.

[2] She was torpedoed on 21 October 1941 by the German submarine U-79 but did not sink was towed and beached at Alexandria and used as a fixed Anti-aircraft platform.