| Radviliskis to Smolyan | 983.64 mi (1,583.02 km) |
| Radviliskis to Sofia | 905.18 mi (1,456.74 km) |
| Radviliskis to Sopot | 910.15 mi (1,464.75 km) |
| Radviliskis to Sozopol | 943.12 mi (1,517.81 km) |
| Radviliskis to Sredets | 943.54 mi (1,518.48 km) |
| Radviliskis to Stamboliyski | 945.31 mi (1,521.32 km) |
| Radviliskis to Stara Zagora | 928.31 mi (1,493.97 km) |
| Radviliskis to Svilengrad | 976.90 mi (1,572.17 km) |
| Radviliskis to Svishtov | 845.54 mi (1,360.77 km) |
| Radviliskis to Targovishte | 877.51 mi (1,412.22 km) |
| Radviliskis to Teteven | 890.72 mi (1,433.48 km) |
| Radviliskis to Troyan | 893.97 mi (1,438.70 km) |
| Radviliskis to Tryavna | 897.80 mi (1,444.87 km) |
| Radviliskis to Tutrakan | 823.02 mi (1,324.52 km) |
| Radviliskis to Varna | 890.77 mi (1,433.56 km) |
