| Boppard to Navodari | 1,062.14 mi (1,709.35 km) |
| Boppard to Negresti-Oas | 733.81 mi (1,180.95 km) |
| Boppard to Nehoiu | 928.66 mi (1,494.53 km) |
| Boppard to Ocna Mures | 791.38 mi (1,273.61 km) |
| Boppard to Odobesti | 948.52 mi (1,526.50 km) |
| Boppard to Odorheiu Secuiesc | 855.84 mi (1,377.34 km) |
| Boppard to Oltenita | 986.66 mi (1,587.87 km) |
| Boppard to Onesti | 921.15 mi (1,482.45 km) |
| Boppard to Oradea | 688.27 mi (1,107.67 km) |
| Boppard to Orastie | 780.15 mi (1,255.52 km) |
| Boppard to Oravita | 746.13 mi (1,200.78 km) |
| Boppard to Orsova | 787.15 mi (1,266.80 km) |
| Boppard to Otelu Rosu | 755.92 mi (1,216.53 km) |
| Boppard to Otopeni | 946.02 mi (1,522.47 km) |
| Boppard to Ovidiu | 1,061.63 mi (1,708.53 km) |
