| Castelldefels to Oerlinghausen | 802.90 mi (1,292.14 km) |
| Castelldefels to Oestrich-Winkel | 668.54 mi (1,075.91 km) |
| Castelldefels to Offenburg | 575.46 mi (926.11 km) |
| Castelldefels to Oftersheim | 644.03 mi (1,036.47 km) |
| Castelldefels to Ohrdruf | 780.76 mi (1,256.51 km) |
| Castelldefels to Ohringen | 657.61 mi (1,058.33 km) |
| Castelldefels to Olbernhau | 845.41 mi (1,360.55 km) |
| Castelldefels to Olching | 661.42 mi (1,064.46 km) |
| Castelldefels to Oldenburg | 869.60 mi (1,399.48 km) |
| Castelldefels to Oldenburg in Holstein | 988.23 mi (1,590.40 km) |
| Castelldefels to Olfen | 765.05 mi (1,231.23 km) |
| Castelldefels to Olpe | 728.24 mi (1,171.98 km) |
| Castelldefels to Olsberg | 761.18 mi (1,225.00 km) |
| Castelldefels to Oranienburg | 951.42 mi (1,531.17 km) |
| Castelldefels to Ortenberg | 712.97 mi (1,147.41 km) |
