| Seclin to Smolyan | 1,202.88 mi (1,935.84 km) |
| Seclin to Sofia | 1,100.24 mi (1,770.67 km) |
| Seclin to Sopot | 1,160.61 mi (1,867.83 km) |
| Seclin to Sozopol | 1,293.08 mi (2,081.01 km) |
| Seclin to Sredets | 1,274.65 mi (2,051.35 km) |
| Seclin to Stamboliyski | 1,172.84 mi (1,887.51 km) |
| Seclin to Stara Zagora | 1,206.61 mi (1,941.85 km) |
| Seclin to Svilengrad | 1,256.53 mi (2,022.20 km) |
| Seclin to Svishtov | 1,148.34 mi (1,848.07 km) |
| Seclin to Targovishte | 1,214.12 mi (1,953.93 km) |
| Seclin to Teteven | 1,129.96 mi (1,818.50 km) |
| Seclin to Troyan | 1,149.93 mi (1,850.64 km) |
| Seclin to Tryavna | 1,183.20 mi (1,904.17 km) |
| Seclin to Tutrakan | 1,186.53 mi (1,909.53 km) |
| Seclin to Varna | 1,272.00 mi (2,047.09 km) |
