| Alton to Smolyan | 1,381.08 mi (2,222.64 km) |
| Alton to Sofia | 1,278.78 mi (2,058.01 km) |
| Alton to Sopot | 1,339.70 mi (2,156.04 km) |
| Alton to Sozopol | 1,472.66 mi (2,370.01 km) |
| Alton to Sredets | 1,454.16 mi (2,340.24 km) |
| Alton to Stamboliyski | 1,351.46 mi (2,174.97 km) |
| Alton to Stara Zagora | 1,385.84 mi (2,230.30 km) |
| Alton to Svilengrad | 1,435.56 mi (2,310.30 km) |
| Alton to Svishtov | 1,327.93 mi (2,137.09 km) |
| Alton to Targovishte | 1,393.73 mi (2,242.99 km) |
| Alton to Teteven | 1,309.06 mi (2,106.73 km) |
| Alton to Troyan | 1,329.15 mi (2,139.06 km) |
| Alton to Tryavna | 1,362.59 mi (2,192.88 km) |
| Alton to Tutrakan | 1,366.06 mi (2,198.47 km) |
| Alton to Varna | 1,451.59 mi (2,336.10 km) |
