World Sea Ports
| Port Name | Port Code | Country Name |
|---|---|---|
| Otranto | ITOTO | Italy |
| Otsa | EEOTS | Estonia |
| Otsu, Ibaraki | JPOSJ | Japan |
| Otsu, Shiga | JPOTU | Japan |
| Otsuchi | JPOTJ | Japan |
| Ottawa | CAOTT | Canada |
| Ottawa Lake | USOTL | United States of America (the) |
| Ottendorf | DESXD | Germany |
| Ottensheim | ATOSH | Austria |
| Otterbäcken | SEOTT | Sweden |