| Locality | Post Code |
|---|---|
| Jabatan Laut, Serasa | BT1728 |
| Jabatan Pelabuhan-Pelabuhan, Serasa | BT1728 |
| Kampong Bukit Kabun, Serasa | BT2928 |
| Kampong Kapok, Serasa | BT2328 |
| Kampong Masjid Lama, Serasa | BT1928 |
| Kampong Meragang, Serasa | BT2728 |
| Kampong Pelumpong, Serasa | BT1328, BT3528 |
| Kampong Pengalayan, Serasa | BT3128 |
| Kampong Pulau Muara Besar, Serasa | BT3328 |
| Kampong Sabun, Serasa | BT2128 |
| Kampong Serasa, Serasa | BT1728 |
| Kampong Tanjong Batu, Serasa | BT1528 |
| Pekan Muara, Serasa | BT1128 |
| Brunei Muara Postal Codes | |
|---|---|
| Tamoi | Sungai Kedayan |
| Sungai Kebun | Serasa |
| Sengkurong | Saba |
| Peramu | Pangkalan Batu |
| Mentiri | Lumapas |
| Kota Batu | Kilanas |
| Kianggeh | Gadong |
| Burong Pinggai Ayer | Berakas B |
| Berakas A | Bandar Seri Begawan |