| London Colney to Orbetello | 837.66 mi (1,348.09 km) |
| London Colney to Oria | 1,151.64 mi (1,853.39 km) |
| London Colney to Oristano | 920.55 mi (1,481.49 km) |
| London Colney to Orta Nova | 1,042.24 mi (1,677.33 km) |
| London Colney to Orte | 872.76 mi (1,404.56 km) |
| London Colney to Ortona | 944.78 mi (1,520.48 km) |
| London Colney to Orvieto | 850.07 mi (1,368.06 km) |
| London Colney to Orzinuovi | 639.21 mi (1,028.71 km) |
| London Colney to Osimo | 855.74 mi (1,377.18 km) |
| London Colney to Ospitaletto | 636.14 mi (1,023.76 km) |
| London Colney to Ostuni | 1,137.90 mi (1,831.27 km) |
| London Colney to Ottaviano | 1,026.96 mi (1,652.74 km) |
| London Colney to Ovada | 639.06 mi (1,028.47 km) |
| London Colney to Ozieri | 887.65 mi (1,428.54 km) |
| London Colney to Paceco | 1,135.50 mi (1,827.40 km) |
