| Portimao to Orbetello | 1,107.66 mi (1,782.61 km) |
| Portimao to Oria | 1,422.54 mi (2,289.35 km) |
| Portimao to Oristano | 943.97 mi (1,519.18 km) |
| Portimao to Orta Nova | 1,325.07 mi (2,132.50 km) |
| Portimao to Orte | 1,166.48 mi (1,877.27 km) |
| Portimao to Ortona | 1,266.29 mi (2,037.90 km) |
| Portimao to Orvieto | 1,156.45 mi (1,861.12 km) |
| Portimao to Orzinuovi | 1,112.38 mi (1,790.21 km) |
| Portimao to Osimo | 1,235.78 mi (1,988.79 km) |
| Portimao to Ospitaletto | 1,123.00 mi (1,807.30 km) |
| Portimao to Ostuni | 1,420.26 mi (2,285.69 km) |
| Portimao to Ottaviano | 1,258.43 mi (2,025.24 km) |
| Portimao to Ovada | 1,033.48 mi (1,663.22 km) |
| Portimao to Ozieri | 971.54 mi (1,563.54 km) |
| Portimao to Paceco | 1,154.04 mi (1,857.25 km) |
