World Sea Ports
| Port Name | Port Code | Country Name |
|---|---|---|
| Mayo | USMY6 | United States of America (the) |
| Mayong | CNMAY | China |
| Mayville | USAY7 | United States of America (the) |
| Mazamitla | MXMAZ | Mexico |
| Mazara del Vallo | ITMAZ | Italy |
| Mazatlan | MXMZT | Mexico |
| McCleary | USQMW | United States of America (the) |
| McDonald Island | HMMCD | Heard Island and McDonald Islands |
| McEwen | USZWM | United States of America (the) |
| McFarland | USMF6 | United States of America (the) |