604 Squadron was initially disbanded in April 1945 as part of a reduction of the British Armed Forces near the end of the war.

The squadron spent the first several months of World War II flying defensive patrols in support of coastal convoys.

During the squadron's stay at RAF Manston that Flying Officer Alistair Hunter and Sergeant Gordon Thomas shot down a Luftwaffe Heinkel 115 floatplane shortly after midnight on 18 June 1940, during the first major night raid over the United Kingdom.

The former was part of RAF Fighter Command policy, and greatly improved air-to-air and air-to ground communication.

In February 1944, the squadron was allocated to the 2nd Tactical Air Force and began conversion to the de Havilland Mosquito.

[9] A notable member of the squadron, later awarded a posthumous George Cross, was John Quinton DFC.

It was initially equipped with Spitfire LF.16s but converted to jets in November 1949 when de Havilland Vampires arrived.

These were replaced by Gloster Meteors in August 1952 but this was only for a few years as the squadron was disbanded on 10 March 1957, along with all the flying units of the Royal Auxiliary Air Force.