531 (Glamorgan) Coast Regiment RA (TA) was formed from the Glamorgan Heavy Regiment RA(TA), in September 1940. RHQ was disbanded and the batteries joined 570 Coast Regiment RA (TA) in December 1942. 531 (Glamorgan) Coast Regiment RA (TA) was not re-formed.
Illustrations of the formation badges under which a unit served or supported are given. This is no guarantee that the unit used this formations badge.
| Sep 40 | Formed from Glamorgan Heavy Regiment | Cardiff, UK | |
| Sep 40 |  |
Western Command, Cardiff Fire Command | Cardiff, UK |
| Nov 41 | |
Western Command, Docks Fire Command | Cardiff, UK |
| Dec 42 | Disbanded |
Batteries
| Sep 40 | A, B |
| Oct 40 | A |
| Dec 40 | A, 365 (Portishead), 366 (Steep Holm South) |
| Apr 41 | 130, 192, 365, 366 |
| Jul 41 | 130, 145, 170, 192, 365, 366 |
| Aug 41 | 130, 145, 188, 192, 365, 366 |
| Oct 41 | 130, 145, 188, 189, 192, 365, 366 |
| Nov 41 | 130, 145, 188, 189, 192, 365, 366, 427 |
| Dec 41 | 130, 427, 430 |
| Jun 42 | 130, 430 |
| Jul 42 | 130, 187, 430 |
| Oct 42 | 170, 187, 430 |
Gun Sites Occupied
365 Battery
| Dates | Gun Site | Guns |
| Aug 40-Dec 41 | Portished | 2 x 6 inch Guns |