| Welwyn Garden City to Smolyan | 1,364.83 mi (2,196.48 km) |
| Welwyn Garden City to Sofia | 1,261.77 mi (2,030.63 km) |
| Welwyn Garden City to Sopot | 1,321.01 mi (2,125.96 km) |
| Welwyn Garden City to Sozopol | 1,451.09 mi (2,335.31 km) |
| Welwyn Garden City to Sredets | 1,433.28 mi (2,306.64 km) |
| Welwyn Garden City to Stamboliyski | 1,334.21 mi (2,147.20 km) |
| Welwyn Garden City to Stara Zagora | 1,366.55 mi (2,199.25 km) |
| Welwyn Garden City to Svilengrad | 1,417.05 mi (2,280.52 km) |
| Welwyn Garden City to Svishtov | 1,306.30 mi (2,102.29 km) |
| Welwyn Garden City to Targovishte | 1,371.59 mi (2,207.35 km) |
| Welwyn Garden City to Teteven | 1,290.35 mi (2,076.61 km) |
| Welwyn Garden City to Troyan | 1,309.96 mi (2,108.18 km) |
| Welwyn Garden City to Tryavna | 1,342.52 mi (2,160.57 km) |
| Welwyn Garden City to Tutrakan | 1,342.10 mi (2,159.90 km) |
| Welwyn Garden City to Varna | 1,428.13 mi (2,298.35 km) |
