As a box code, 3700 is used for 9 post office box locations.
PO Boxes using 3700
| Suburb | Town | Province |
|---|---|---|
| Cliffdale | Hammarsdale | KwaZulu-Natal |
| Enhlanzeni | Hammarsdale | KwaZulu-Natal |
| Fredville | Hammarsdale | KwaZulu-Natal |
| Hammarsdale | Hammarsdale | KwaZulu-Natal |
| Mophela | Hammarsdale | KwaZulu-Natal |
| Mpuma | Hammarsdale | KwaZulu-Natal |
| Phanekeni | Hammarsdale | KwaZulu-Natal |
| Sankontshe | Hammarsdale | KwaZulu-Natal |
| Shawuka | Hammarsdale | KwaZulu-Natal |