| Sierre to Smolyan | 911.82 mi (1,467.43 km) |
| Sierre to Sofia | 815.61 mi (1,312.60 km) |
| Sierre to Sopot | 883.44 mi (1,421.77 km) |
| Sierre to Sozopol | 1,028.59 mi (1,655.35 km) |
| Sierre to Sredets | 1,006.71 mi (1,620.14 km) |
| Sierre to Stamboliyski | 887.60 mi (1,428.45 km) |
| Sierre to Stara Zagora | 931.49 mi (1,499.09 km) |
| Sierre to Svilengrad | 975.96 mi (1,570.65 km) |
| Sierre to Svishtov | 888.57 mi (1,430.02 km) |
| Sierre to Targovishte | 955.31 mi (1,537.43 km) |
| Sierre to Teteven | 853.81 mi (1,374.07 km) |
| Sierre to Troyan | 875.84 mi (1,409.52 km) |
| Sierre to Tryavna | 913.18 mi (1,469.62 km) |
| Sierre to Tutrakan | 940.02 mi (1,512.82 km) |
| Sierre to Varna | 1,019.45 mi (1,640.65 km) |
