| Piran to Oberkirch | 331.27 mi (533.12 km) |
| Piran to Obernburg am Main | 362.01 mi (582.59 km) |
| Piran to Obernkirchen | 507.31 mi (816.44 km) |
| Piran to Oberschleissheim | 210.45 mi (338.68 km) |
| Piran to Oberstdorf | 203.43 mi (327.39 km) |
| Piran to Obertraubling | 246.42 mi (396.58 km) |
| Piran to Obertshausen | 382.75 mi (615.97 km) |
| Piran to Oberursel | 397.13 mi (639.11 km) |
| Piran to Ochsenfurt | 328.13 mi (528.07 km) |
| Piran to Ochsenhausen | 245.33 mi (394.82 km) |
| Piran to Ochtrup | 544.39 mi (876.11 km) |
| Piran to Odenthal | 481.97 mi (775.66 km) |
| Piran to Oelde | 500.55 mi (805.55 km) |
| Piran to Oelsnitz | 343.90 mi (553.46 km) |
| Piran to Oer-Erkenschwick | 511.26 mi (822.80 km) |
