| Portimao to Navodari | 1,989.18 mi (3,201.27 km) |
| Portimao to Negresti-Oas | 1,772.45 mi (2,852.48 km) |
| Portimao to Nehoiu | 1,880.36 mi (3,026.14 km) |
| Portimao to Ocna Mures | 1,772.76 mi (2,852.99 km) |
| Portimao to Odobesti | 1,919.67 mi (3,089.40 km) |
| Portimao to Odorheiu Secuiesc | 1,839.94 mi (2,961.09 km) |
| Portimao to Oltenita | 1,890.79 mi (3,042.93 km) |
| Portimao to Onesti | 1,908.97 mi (3,072.19 km) |
| Portimao to Oradea | 1,691.75 mi (2,722.61 km) |
| Portimao to Orastie | 1,735.60 mi (2,793.18 km) |
| Portimao to Oravita | 1,654.49 mi (2,662.65 km) |
| Portimao to Orsova | 1,685.95 mi (2,713.28 km) |
| Portimao to Otelu Rosu | 1,691.63 mi (2,722.42 km) |
| Portimao to Otopeni | 1,864.56 mi (3,000.72 km) |
| Portimao to Ovidiu | 1,986.46 mi (3,196.89 km) |
