| Zonguldak to Orbetello | 1,057.47 mi (1,701.83 km) |
| Zonguldak to Oria | 741.01 mi (1,192.54 km) |
| Zonguldak to Oristano | 1,217.02 mi (1,958.60 km) |
| Zonguldak to Orta Nova | 832.69 mi (1,340.08 km) |
| Zonguldak to Orte | 997.64 mi (1,605.54 km) |
| Zonguldak to Ortona | 895.27 mi (1,440.80 km) |
| Zonguldak to Orvieto | 1,010.98 mi (1,627.02 km) |
| Zonguldak to Orzinuovi | 1,126.64 mi (1,813.14 km) |
| Zonguldak to Osimo | 941.92 mi (1,515.88 km) |
| Zonguldak to Ospitaletto | 1,121.12 mi (1,804.27 km) |
| Zonguldak to Ostuni | 741.04 mi (1,192.59 km) |
| Zonguldak to Ottaviano | 900.58 mi (1,449.35 km) |
| Zonguldak to Ovada | 1,185.31 mi (1,907.57 km) |
| Zonguldak to Ozieri | 1,186.38 mi (1,909.30 km) |
| Zonguldak to Paceco | 1,048.34 mi (1,687.15 km) |
