| Sliven to Opwijk | 1,186.75 mi (1,909.90 km) |
| Sliven to Ostend | 1,244.42 mi (2,002.70 km) |
| Sliven to Oud-Heverlee | 1,163.80 mi (1,872.95 km) |
| Sliven to Oud-Turnhout | 1,163.25 mi (1,872.06 km) |
| Sliven to Oudenaarde | 1,207.99 mi (1,944.08 km) |
| Sliven to Oudenburg | 1,240.16 mi (1,995.85 km) |
| Sliven to Oupeye | 1,120.88 mi (1,803.88 km) |
| Sliven to Overijse | 1,168.06 mi (1,879.81 km) |
| Sliven to Overpelt | 1,143.29 mi (1,839.95 km) |
| Sliven to Paal | 1,148.40 mi (1,848.17 km) |
| Sliven to Peer | 1,139.58 mi (1,833.97 km) |
| Sliven to Pepinster | 1,110.21 mi (1,786.72 km) |
| Sliven to Peruwelz | 1,201.39 mi (1,933.45 km) |
| Sliven to Perwez | 1,152.70 mi (1,855.10 km) |
| Sliven to Philippeville | 1,154.08 mi (1,857.31 km) |
