| Union to Smolyan | 5,587.79 mi (8,992.68 km) |
| Union to Sofia | 5,483.72 mi (8,825.19 km) |
| Union to Sopot | 5,538.13 mi (8,912.76 km) |
| Union to Sozopol | 5,655.47 mi (9,101.60 km) |
| Union to Sredets | 5,641.02 mi (9,078.35 km) |
| Union to Stamboliyski | 5,555.12 mi (8,940.09 km) |
| Union to Stara Zagora | 5,581.29 mi (8,982.21 km) |
| Union to Svilengrad | 5,633.80 mi (9,066.72 km) |
| Union to Svishtov | 5,513.03 mi (8,872.37 km) |
| Union to Targovishte | 5,574.75 mi (8,971.69 km) |
| Union to Teteven | 5,507.71 mi (8,863.80 km) |
| Union to Troyan | 5,525.68 mi (8,892.71 km) |
| Union to Tryavna | 5,554.78 mi (8,939.56 km) |
| Union to Tutrakan | 5,536.67 mi (8,910.41 km) |
| Union to Varna | 5,623.28 mi (9,049.80 km) |
