| Calais to Oestrich-Winkel | 277.89 mi (447.22 km) |
| Calais to Offenburg | 320.97 mi (516.55 km) |
| Calais to Oftersheim | 317.00 mi (510.17 km) |
| Calais to Ohrdruf | 386.75 mi (622.41 km) |
| Calais to Ohringen | 359.62 mi (578.75 km) |
| Calais to Olbernhau | 500.98 mi (806.24 km) |
| Calais to Olching | 464.00 mi (746.74 km) |
| Calais to Oldenburg | 309.68 mi (498.39 km) |
| Calais to Oldenburg in Holstein | 443.33 mi (713.48 km) |
| Calais to Olfen | 244.37 mi (393.27 km) |
| Calais to Olpe | 259.96 mi (418.36 km) |
| Calais to Olsberg | 288.46 mi (464.24 km) |
| Calais to Oranienburg | 500.90 mi (806.11 km) |
| Calais to Ortenberg | 317.88 mi (511.57 km) |
| Calais to Oschatz | 488.02 mi (785.40 km) |
