| Romanshorn to Oberkirch | 89.15 mi (143.47 km) |
| Romanshorn to Obernburg am Main | 157.60 mi (253.63 km) |
| Romanshorn to Obernkirchen | 325.11 mi (523.22 km) |
| Romanshorn to Oberschleissheim | 112.82 mi (181.57 km) |
| Romanshorn to Oberstdorf | 44.38 mi (71.42 km) |
| Romanshorn to Obertraubling | 161.53 mi (259.96 km) |
| Romanshorn to Obertshausen | 174.58 mi (280.96 km) |
| Romanshorn to Oberursel | 185.80 mi (299.01 km) |
| Romanshorn to Ochsenfurt | 147.77 mi (237.81 km) |
| Romanshorn to Ochsenhausen | 44.60 mi (71.77 km) |
| Romanshorn to Ochtrup | 334.88 mi (538.94 km) |
| Romanshorn to Odenthal | 260.08 mi (418.56 km) |
| Romanshorn to Oelde | 299.89 mi (482.62 km) |
| Romanshorn to Oelsnitz | 234.69 mi (377.70 km) |
| Romanshorn to Oer-Erkenschwick | 297.13 mi (478.19 km) |
