| Kocaeli to Orbetello | 971.35 mi (1,563.24 km) |
| Kocaeli to Oria | 643.86 mi (1,036.20 km) |
| Kocaeli to Oristano | 1,122.00 mi (1,805.68 km) |
| Kocaeli to Orta Nova | 740.47 mi (1,191.67 km) |
| Kocaeli to Orte | 911.55 mi (1,467.00 km) |
| Kocaeli to Ortona | 808.60 mi (1,301.32 km) |
| Kocaeli to Orvieto | 926.17 mi (1,490.53 km) |
| Kocaeli to Orzinuovi | 1,054.94 mi (1,697.76 km) |
| Kocaeli to Osimo | 861.39 mi (1,386.27 km) |
| Kocaeli to Ospitaletto | 1,050.32 mi (1,690.32 km) |
| Kocaeli to Ostuni | 645.10 mi (1,038.18 km) |
| Kocaeli to Ottaviano | 806.46 mi (1,297.87 km) |
| Kocaeli to Ovada | 1,109.30 mi (1,785.25 km) |
| Kocaeli to Ozieri | 1,093.42 mi (1,759.70 km) |
| Kocaeli to Paceco | 945.61 mi (1,521.82 km) |
