| Castellabate to Oegstgeest | 960.98 mi (1,546.55 km) |
| Castellabate to Oirschot | 901.91 mi (1,451.48 km) |
| Castellabate to Oisterwijk | 909.09 mi (1,463.03 km) |
| Castellabate to Oldebroek | 943.54 mi (1,518.48 km) |
| Castellabate to Oldenzaal | 914.27 mi (1,471.38 km) |
| Castellabate to Ommen | 936.76 mi (1,507.57 km) |
| Castellabate to Oosterend | 973.29 mi (1,566.36 km) |
| Castellabate to Oosterhout | 920.92 mi (1,482.08 km) |
| Castellabate to Oosterwolde | 968.00 mi (1,557.84 km) |
| Castellabate to Oostzaan | 965.29 mi (1,553.48 km) |
| Castellabate to Opmeer | 979.18 mi (1,575.84 km) |
| Castellabate to Oss | 912.04 mi (1,467.78 km) |
| Castellabate to Oud-Beijerland | 942.10 mi (1,516.16 km) |
| Castellabate to Oudenbosch | 926.31 mi (1,490.74 km) |
| Castellabate to Oudewater | 941.83 mi (1,515.72 km) |
