As a box code, 0300 is used for 19 post office box locations.
Suburbs using 0300 as street code
| Suburb | Town | Province |
|---|---|---|
| Boitekong Ext 10 | Boitekong | North West |
| Boitekong Ext 15 | Boitekong | North West |
| Boitekong Ext 22 | Boitekong | North West |
PO Boxes using 0300
| Suburb | Town | Province |
|---|---|---|
| Cashan Ext 20 | Rustenburg | North West |
| Cashan Ext 33 | Rustenburg | North West |
| Geelhoutpark | Rustenburg | North West |
| Geelhoutpark Ext 1 | Rustenburg | North West |
| Geelhoutpark Ext 13 | Rustenburg | North West |
| Geelhoutpark Ext 14 | Rustenburg | North West |
| Geelhoutpark Ext 4 | Rustenburg | North West |
| Geelhoutpark Ext 6 | Rustenburg | North West |
| Geelhoutpark Ext 9 | Rustenburg | North West |
| Klooftuine | Rustenburg | North West |
| Meriting | Rustenburg | North West |
| Meriting Ext 1 | Rustenburg | North West |
| Modikoe | Rustenburg | North West |
| Rustenburg | Rustenburg | North West |
| Waterfall Village | Rustenburg | North West |
| Waterkloof Hills | Rustenburg | North West |
| Yellowwoodpark | Rustenburg | North West |
| Yellowwoodpark Ext 6 | Rustenburg | North West |
| Yellowwoodpark Ext 9 | Rustenburg | North West |