| Piraeus to Oerlinghausen | 1,209.58 mi (1,946.63 km) |
| Piraeus to Oestrich-Winkel | 1,135.36 mi (1,827.18 km) |
| Piraeus to Offenburg | 1,070.84 mi (1,723.36 km) |
| Piraeus to Oftersheim | 1,087.08 mi (1,749.48 km) |
| Piraeus to Ohrdruf | 1,091.65 mi (1,756.84 km) |
| Piraeus to Ohringen | 1,048.45 mi (1,687.32 km) |
| Piraeus to Olbernhau | 1,014.12 mi (1,632.07 km) |
| Piraeus to Olching | 940.80 mi (1,514.06 km) |
| Piraeus to Oldenburg | 1,282.80 mi (2,064.47 km) |
| Piraeus to Oldenburg in Holstein | 1,280.34 mi (2,060.51 km) |
| Piraeus to Olfen | 1,235.51 mi (1,988.37 km) |
| Piraeus to Olpe | 1,188.07 mi (1,912.01 km) |
| Piraeus to Olsberg | 1,184.11 mi (1,905.64 km) |
| Piraeus to Oranienburg | 1,138.69 mi (1,832.55 km) |
| Piraeus to Ortenberg | 1,117.87 mi (1,799.03 km) |
