| Rhondda to Oberkirch | 551.91 mi (888.21 km) |
| Rhondda to Obernburg am Main | 562.06 mi (904.54 km) |
| Rhondda to Obernkirchen | 535.14 mi (861.23 km) |
| Rhondda to Oberschleissheim | 704.30 mi (1,133.46 km) |
| Rhondda to Oberstdorf | 678.30 mi (1,091.62 km) |
| Rhondda to Obertraubling | 710.36 mi (1,143.22 km) |
| Rhondda to Obertshausen | 544.43 mi (876.18 km) |
| Rhondda to Oberursel | 530.95 mi (854.49 km) |
| Rhondda to Ochsenfurt | 605.40 mi (974.30 km) |
| Rhondda to Ochsenhausen | 642.70 mi (1,034.33 km) |
| Rhondda to Ochtrup | 453.56 mi (729.93 km) |
| Rhondda to Odenthal | 456.21 mi (734.20 km) |
| Rhondda to Oelde | 494.79 mi (796.28 km) |
| Rhondda to Oelsnitz | 681.12 mi (1,096.15 km) |
| Rhondda to Oer-Erkenschwick | 457.16 mi (735.72 km) |
