World Sea Ports
| Port Name | Port Code | Country Name |
|---|---|---|
| Onega | RUONG | Russian Federation (the) |
| Oneglia | ITONE | Italy |
| Onehunga (Manukau Harbour) | NZONE | New Zealand |
| Ongachi | JPOGC | Japan |
| Oniike | JPONJ | Japan |
| Oniki | JPONK | Japan |
| Onishi | JPONI | Japan |
| Oniwaki | JPONW | Japan |
| Onjal | INONJ | India |
| Onkerzele | BEOZL | Belgium |