| Barcelos to Orbetello | 1,018.18 mi (1,638.60 km) |
| Barcelos to Oria | 1,365.18 mi (2,197.05 km) |
| Barcelos to Oristano | 906.57 mi (1,458.98 km) |
| Barcelos to Orta Nova | 1,256.29 mi (2,021.80 km) |
| Barcelos to Orte | 1,077.82 mi (1,734.59 km) |
| Barcelos to Ortona | 1,180.85 mi (1,900.39 km) |
| Barcelos to Orvieto | 1,062.85 mi (1,710.49 km) |
| Barcelos to Orzinuovi | 965.77 mi (1,554.25 km) |
| Barcelos to Osimo | 1,130.59 mi (1,819.50 km) |
| Barcelos to Ospitaletto | 974.27 mi (1,567.94 km) |
| Barcelos to Ostuni | 1,359.46 mi (2,187.84 km) |
| Barcelos to Ottaviano | 1,198.21 mi (1,928.33 km) |
| Barcelos to Ovada | 895.66 mi (1,441.43 km) |
| Barcelos to Ozieri | 918.75 mi (1,478.59 km) |
| Barcelos to Paceco | 1,147.50 mi (1,846.72 km) |
