| Sint-Niklaas to Oestrich-Winkel | 187.78 mi (302.21 km) |
| Sint-Niklaas to Offenburg | 251.93 mi (405.44 km) |
| Sint-Niklaas to Oftersheim | 232.42 mi (374.05 km) |
| Sint-Niklaas to Ohrdruf | 287.83 mi (463.22 km) |
| Sint-Niklaas to Ohringen | 273.47 mi (440.11 km) |
| Sint-Niklaas to Olbernhau | 401.97 mi (646.91 km) |
| Sint-Niklaas to Olching | 380.71 mi (612.70 km) |
| Sint-Niklaas to Oldenburg | 220.36 mi (354.63 km) |
| Sint-Niklaas to Oldenburg in Holstein | 355.58 mi (572.26 km) |
| Sint-Niklaas to Olfen | 145.02 mi (233.39 km) |
| Sint-Niklaas to Olpe | 160.88 mi (258.91 km) |
| Sint-Niklaas to Olsberg | 188.49 mi (303.34 km) |
| Sint-Niklaas to Oranienburg | 402.50 mi (647.76 km) |
| Sint-Niklaas to Ortenberg | 222.25 mi (357.67 km) |
| Sint-Niklaas to Oschatz | 388.10 mi (624.59 km) |
