1 Anti-Aircraft Regiment Hong Kong Singapore RA was formed with a battery from 3 Anti-Aircraft Regiment RA and two new batteries. The Regiment was captured at Singapore in February 1942. In March 1944 the Regiment was re-formed in Aden by the re-designation of 5 Coast Regiment RA. It was disbanded at Visapur, India in October 1946.
| Oct 38 | Formed from a battery from 3 Anti-Aircraft Regiment RA | Singapore |
| Sep 39 | Malaya Command | Singapore |
| Aug 40 | Became 1 Heavy Anti-Aircraft Regiment HKS RA | Singapore |
| Feb 42 | Captured at Singapore | Singapore |
| Mar 44 | Re-formed by re-designation of 5 Coast Regiment RA | Aden |
Batteries
| Oct 38 | 6, 9, 11 |
| Jan 39 | 6, 9, 10 |
| Jan 40 | 6, 9, 10, 16, 23 |
| Feb 40 | 6, 9, 10, 16 |
| Aug 40 | 6, 9, 10, 16 (LAA) |
| Sep 41 | 6, 9, 10 |
| Feb 42 | Captured |
| Mar 44 – re-formed in Aden | 15, 23, 24 |