517 (Thames & Medway) Coast Regiment RA (TA) was formed from a part of the Thames & Medway Heavy Regiment RA (TA), in July 1940. RHQ was placed in to suspended animation in June 1945. 517 (Thames & Medway) Coast Regiment RA (TA) was disbanded in January 1947.
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.
| Jul 40 | Formed from part of Thames & Medway Heavy Regiment | ||
| Jul 40 |  |
Eastern Command | UK |
| Dec 42 | Thames Fire Command | Canvey Island, Essex, UK | |
| Jun 45 | Suspended animation |
Batteries
| Jul 40 | A, B |
| Dec 40 | A, 332 (Foulness), 356 (Coalhouse Fort), 419 |
| Apr 41 | 167 (Dead Man’s Point), 168 (Scars Elbow), 332, 356, 419 (Shoeburyness) |
| Sep 41 | 167, 168, 332, 356, 357, 419 |
| Oct 41 | 109, 167, 168 (St Mary’s Bay), 332, 356, 419 |
| Feb 42 | 167, 168, 356, 419, 425 (Shornemead) |
| Mar 43 | 168, 286, 356, 419, 425 |
| Apr 44 | 220, 356, 419, 425 |
Equipment
| 2 x 6 inch MkXII Guns | Foulness | 332 Battery |
| 2 x 5.5 inch Guns | Coalhouse Fort | 356 Battery |
| 2 x 5.5 inch Guns | Shornemead Fort | 425 Battery from Feb 42 |