S = Secure Speech modification to Avionics, main visual difference is the tail boom lower aerial is larger than the HAS 2/3 aerial and a pointed probe on it. First conversion from a standard HAS3 to HAS3S started November 1987 on ZD268 and 67 conversions took place including the HAS3(ICE) and HAS3(GM) aircraft that were modified
Airframes (30)
| C/N | Model | Built | Reg | |
|---|---|---|---|---|
| 010 | has.2 | 1977 |  XZ233 | |
| 019 | has.2 | 1977 | XZ237 | |
| 067 | has.2 | 1978 | XZ245 | |
| 080 | has.2 | 1978 | XZ248 | |
| 094 | has.2 | 1978 | XZ254 | |
| 099 | has.2 | 1978 | XZ255 | |
| 103 | has.2 | 1979 | XZ257 | |
| 113 | has.2 | 1979 | XZ690 | |
| 117 | has.2 | 1979 | XZ691 | |
| 132 | has.2 | 1979 | XZ695 | |
| 199 | has.2 | 1980 | XZ727 | |
| 200 | has.2 | 1980 | XZ728 | |
| 243 | has.3 | 1981 | ZD249 | 637 |
| 251 | has.3 | 1982 | ZD251 | |
| 255 | has.3 | ZD252 | ||
| 259 | has.3 | ZD254 | ||
| 267 | has.3 | 1982 | ZD257 | |
| 270 | has.3 | 1982 | ZD258 | |
| 286 | has.3 | 1983 | ZD259 | |
| 297 | has.3 | 1983 | ZD262 | |
| 299 | has.3 | 1983 | ZD263 | |
| 316 | has.3 | 1985 | ZD565 | |
| 318 | has.3 | 1985 | ZD567 | |
| 334 | has.3s | 1987 | ZF557 | 444-MR |
| 335 | has.3s | 1987 | ZF558 | 336-WK |
| 336 | has.3s | 1987 | ZF559 ZH580  19201 | |
| 337 | has.3s | 1987 | ZF560 | 456 |
| 338 | has.3s | 1988 | ZF561 19202 | |
| 339 | has.3s | 1988 | ZF562 | 320-AZ |
| 340 | has.3s | 1988 | ZF563 | 637 |
Operators
| 1971-2000 | Westland Lynx |
| 1976-2017 | Fleet Air Arm Lynx |
| 1993- | Marinha Portuguesa Lynx |