| Postal Code | Town | County |
|---|---|---|
| 30127 | Simat | Uasin Gishu |
| 40308 | Sindo | Homa Bay |
| 30703 | Singore | Elgeyo-Marakwet |
| 50401 | Sio Port | Busia |
| 20423 | Siongiroi | Bomet |
| 20230 | Siongiroi | Bomet |
| 20326 | Sipili | Laikipia |
| 40636 | Sirembe | Siaya |
| 30213 | Sirende | Trans Nzoia |
| 50208 | Sirisia | Bungoma |