| Opmeer to Orbetello | 765.98 mi (1,232.73 km) |
| Opmeer to Oria | 1,032.63 mi (1,661.86 km) |
| Opmeer to Oristano | 900.62 mi (1,449.41 km) |
| Opmeer to Orta Nova | 932.68 mi (1,501.00 km) |
| Opmeer to Orte | 786.83 mi (1,266.28 km) |
| Opmeer to Ortona | 838.52 mi (1,349.47 km) |
| Opmeer to Orvieto | 764.91 mi (1,231.00 km) |
| Opmeer to Orzinuovi | 552.23 mi (888.73 km) |
| Opmeer to Osimo | 747.58 mi (1,203.12 km) |
| Opmeer to Ospitaletto | 544.96 mi (877.03 km) |
| Opmeer to Ostuni | 1,017.49 mi (1,637.49 km) |
| Opmeer to Ottaviano | 932.83 mi (1,501.25 km) |
| Opmeer to Ovada | 581.72 mi (936.19 km) |
| Opmeer to Ozieri | 858.51 mi (1,381.65 km) |
| Opmeer to Paceco | 1,080.28 mi (1,738.54 km) |
