| Unit Name: | No. 631 Squadron RAF |
| Dates: | 1 December 1943 – 7 February 1949 |
| Branch: | Royal Air Force |
| Role: | anti-aircraft co-operation |
| Command Structure: | No. 70 Group RAF, Air Defence of Great Britain (43-44) No. 70 Group RAF, Fighter Command (44-49) |
| Identification Symbol Label: | Squadron Badge heraldry |
| Identification Symbol 2: | 6D (Dec 1943 – Feb 1949) |
| Identification Symbol 2 Label: | Squadron Codes |
No. 631 Squadron RAF was an anti-aircraft co-operation squadron of the Royal Air Force from 1943 to 1949.
The squadron was formed at RAF Towyn on 1 December 1943, from 1605 Flight and 1628 Flight for anti-aircraft co-operation duties, and operated a variety of aircraft in this role.[1] On 10 May 1945 the squadron moved to RAF Llanbedr. It was disbanded on 11 February 1949 when redesignated No. 20 Squadron RAF.
| December 1943 | February 1945 | Mk.II | ||
| March 1944 | July 1945 | Mk.IIc | ||
| August 1944 | July 1945 | |||
| September 1944 | October 1944 | Mk.I | ||
| May 1945 | May 1947 | Mk.IV | ||
| June 1945 | July 1945 | Mk.Vb | ||
| June 1945 | February 1949 | Mk.XVI | ||
| January 1947 | February 1949 | Mk.I | ||
| August 1948 | February 1949 | F.1 |
| 1 December 1943 | 10 May 1945 | Det. at RAF Llanbedr, Gwynedd, Wales | ||
| 10 May 1945 | 11 February 1949 | RAF Llanbedr, Gwynedd, Wales |