| Caerphilly to Opwijk | 322.56 mi (519.11 km) |
| Caerphilly to Ostend | 265.58 mi (427.42 km) |
| Caerphilly to Oud-Heverlee | 345.00 mi (555.22 km) |
| Caerphilly to Oud-Turnhout | 353.43 mi (568.80 km) |
| Caerphilly to Oudenaarde | 299.23 mi (481.57 km) |
| Caerphilly to Oudenburg | 269.45 mi (433.63 km) |
| Caerphilly to Oupeye | 388.53 mi (625.28 km) |
| Caerphilly to Overijse | 340.02 mi (547.21 km) |
| Caerphilly to Overpelt | 372.85 mi (600.04 km) |
| Caerphilly to Paal | 364.12 mi (585.99 km) |
| Caerphilly to Peer | 375.20 mi (603.83 km) |
| Caerphilly to Pepinster | 398.14 mi (640.74 km) |
| Caerphilly to Peruwelz | 304.27 mi (489.68 km) |
| Caerphilly to Perwez | 354.51 mi (570.53 km) |
| Caerphilly to Philippeville | 351.51 mi (565.71 km) |
