| Code | Name | Region |
|---|---|---|
| GBSDS | Sandside | HLD |
| GBSD5 | Sandtoft | NLN |
| GBSDW | Sandwich | KEN |
| GBSWC | Sandwick | ZET |
| GBSDY | Sandy | CBF |
| GBSNF | Sandycroft | FLN |
| GBSAJ | Sanquhar | DGY |
| GBSRU | Sarisbury | HAM |
| GBSRX | Sark | |
| GBSAU | Saundersfoot | PEM |
| GBSWW | Sawbridgeworth | HRT |
| GBSAS | Sawston | CAM |
| GBXAS | Saxby-all-sts | LIN |
| GBSAX | Saxham | SFK |
| GBSXB | Saxilby | LIN |
| GBSXM | Saxmundham | SFK |
| GBSAL | Saltby | LEC |
| GBSLC | Saltcoats | NAY |
| GBSTH | Salthouse | NFK |
| GBSLX | Saltley | BIR |
| GBSLT | Saltney | FLN |
| GBSIC | Salwick | LAN |
| GBSAM | Samlesbury | LAN |
| GBSDU | Sampford Arundel | SOM |
| GBSAC | Sancreed | CON |
| GBSNJ | Sand | ZET |
| GBNDY | Sanday | ORK |
| GBSAN | Sandbach | CHE |
| GBSDR | Sanderstead | SRY |
| GBSAD | Sandford | DEV |
| GBAFS | Sandford | NSM |
| GBSFT | Sandford On Thames | OXF |
| GBQVG | Sandgate | KEN |
| GBSPI | Sandhaven And Pitullie | ABD |
| GBSUB | Sandhurst | BRC |
| GBSDI | Sandiacre | DBY |
| GBSCW | Saint Nicholas At Wade | KEN |
| GBSOS | Saint Osyth | ESS |
| GBUEN | Saint Ouen | |
| GBPPO | Saint Peter Port | |
| GBSEM | Saint Peter South Elmham | NFK |
| GBSTQ | Saint Quivox | SAY |
| GBSMP | Saint Sampson (golant) | CON |
| GBSSP | Saint Stephen | CON |
| GBASA | Saint-anne's-on-sea | LAN |
| GBSXD | Saintfield | DOW |
| GBSCB | Salcombe | DEV |
| GBSAE | Sale | TRF |
| GBAEN | Salen | HLD |
| GBSFY | Salford | SLF |