| Duffel to Oestrich-Winkel | 170.75 mi (274.79 km) |
| Duffel to Offenburg | 237.30 mi (381.89 km) |
| Duffel to Oftersheim | 215.82 mi (347.33 km) |
| Duffel to Ohrdruf | 271.07 mi (436.24 km) |
| Duffel to Ohringen | 256.65 mi (413.04 km) |
| Duffel to Olbernhau | 385.26 mi (620.01 km) |
| Duffel to Olching | 364.03 mi (585.85 km) |
| Duffel to Oldenburg | 211.00 mi (339.58 km) |
| Duffel to Oldenburg in Holstein | 346.10 mi (556.99 km) |
| Duffel to Olfen | 130.68 mi (210.30 km) |
| Duffel to Olpe | 144.13 mi (231.96 km) |
| Duffel to Olsberg | 172.48 mi (277.58 km) |
| Duffel to Oranienburg | 388.44 mi (625.14 km) |
| Duffel to Ortenberg | 205.02 mi (329.94 km) |
| Duffel to Oschatz | 371.96 mi (598.61 km) |
