| Seia to Smolyan | 1,681.53 mi (2,706.17 km) |
| Seia to Sofia | 1,602.98 mi (2,579.74 km) |
| Seia to Sopot | 1,675.11 mi (2,695.83 km) |
| Seia to Sozopol | 1,826.15 mi (2,938.91 km) |
| Seia to Sredets | 1,801.48 mi (2,899.21 km) |
| Seia to Stamboliyski | 1,668.07 mi (2,684.49 km) |
| Seia to Stara Zagora | 1,722.29 mi (2,771.76 km) |
| Seia to Svilengrad | 1,756.32 mi (2,826.52 km) |
| Seia to Svishtov | 1,699.52 mi (2,735.12 km) |
| Seia to Targovishte | 1,763.29 mi (2,837.75 km) |
| Seia to Teteven | 1,648.98 mi (2,653.78 km) |
| Seia to Troyan | 1,671.87 mi (2,690.62 km) |
| Seia to Tryavna | 1,711.46 mi (2,754.32 km) |
| Seia to Tutrakan | 1,760.45 mi (2,833.18 km) |
| Seia to Varna | 1,830.30 mi (2,945.58 km) |
