| Idar-Oberstein to Oria | 809.82 mi (1,303.28 km) |
| Idar-Oberstein to Oristano | 680.37 mi (1,094.94 km) |
| Idar-Oberstein to Orta Nova | 706.55 mi (1,137.09 km) |
| Idar-Oberstein to Orte | 556.55 mi (895.68 km) |
| Idar-Oberstein to Ortona | 611.16 mi (983.57 km) |
| Idar-Oberstein to Orvieto | 534.57 mi (860.31 km) |
| Idar-Oberstein to Orzinuovi | 321.92 mi (518.08 km) |
| Idar-Oberstein to Osimo | 520.17 mi (837.13 km) |
| Idar-Oberstein to Ospitaletto | 314.55 mi (506.22 km) |
| Idar-Oberstein to Ostuni | 795.12 mi (1,279.62 km) |
| Idar-Oberstein to Ottaviano | 703.65 mi (1,132.41 km) |
| Idar-Oberstein to Ovada | 355.99 mi (572.91 km) |
| Idar-Oberstein to Ozieri | 635.89 mi (1,023.37 km) |
| Idar-Oberstein to Paceco | 850.77 mi (1,369.19 km) |
| Idar-Oberstein to Pachino | 978.45 mi (1,574.66 km) |
