559 Coast Regiment RA was formed as 21 Coast Artillery Group RA at Mumbles with three batteries, in October 1940. It was re-designated 559 Coast Regiment RA in June 1941. RHQ was disbanded in April 1944 and the batteries joined 570 Coast Regiment RA.
| Oct 40 | Formed as 21 Coast Artillery Group | Mumbles, Swansea, UK |
| Jun 41 | Became 559 Coast Regiment | Mumbles, Swansea, UK |
| Dec 42 | Mumbles Fire Command | Mumbles, Swansea, UK |
| Apr 44 | Disbanded |
Batteries
| Oct 40 | 401, 402, B/531 |
| Mar 41 | 166, 401, 402, B/531 |
| Apr 41 | 166, 298, 401, 402 |
| May 41 | 146, 166, 298, 401, 402 |
| Jun 41 | 146, 298, 401, 402 |
| Dec 41 | 146, 298, 401, 402, 431 |
| May 42 | 146, 299, 401, 431 |
| Nov 42 | 146, 299, 422, 431 |
| Dec 42 | 299, 422, 431 |
