World Sea Ports
| Port Name | Port Code | Country Name |
|---|---|---|
| Oostkamp | BEOKP | Belgium |
| Oostkerke | BEOTK | Belgium |
| Oostmahorn | NLOMH | Netherlands |
| Opatija | HROPA | Croatia |
| Opatovac | HROPT | Croatia |
| Ophoven | BEOHN | Belgium |
| Opitter | BEOPI | Belgium |
| Opocno | CZOCX | Czechia |
| Opol | PHOPO | Philippines (the) |
| Oppama | JPOPA | Japan |