| Serpa to Smolyan | 1,723.52 mi (2,773.73 km) |
| Serpa to Sofia | 1,652.36 mi (2,659.22 km) |
| Serpa to Sopot | 1,724.47 mi (2,775.26 km) |
| Serpa to Sozopol | 1,874.99 mi (3,017.50 km) |
| Serpa to Sredets | 1,849.68 mi (2,976.78 km) |
| Serpa to Stamboliyski | 1,713.79 mi (2,758.08 km) |
| Serpa to Stara Zagora | 1,770.45 mi (2,849.27 km) |
| Serpa to Svilengrad | 1,800.26 mi (2,897.24 km) |
| Serpa to Svishtov | 1,755.54 mi (2,825.26 km) |
| Serpa to Targovishte | 1,817.10 mi (2,924.35 km) |
| Serpa to Teteven | 1,700.07 mi (2,736.00 km) |
| Serpa to Troyan | 1,722.82 mi (2,772.61 km) |
| Serpa to Tryavna | 1,762.48 mi (2,836.43 km) |
| Serpa to Tutrakan | 1,819.43 mi (2,928.09 km) |
| Serpa to Varna | 1,884.25 mi (3,032.40 km) |
