| Castel San Pietro Terme to Smolyan | 690.00 mi (1,110.44 km) |
| Castel San Pietro Terme to Sofia | 599.29 mi (964.47 km) |
| Castel San Pietro Terme to Sopot | 669.84 mi (1,078.00 km) |
| Castel San Pietro Terme to Sozopol | 819.10 mi (1,318.22 km) |
| Castel San Pietro Terme to Sredets | 795.71 mi (1,280.57 km) |
| Castel San Pietro Terme to Stamboliyski | 669.31 mi (1,077.15 km) |
| Castel San Pietro Terme to Stara Zagora | 717.98 mi (1,155.48 km) |
| Castel San Pietro Terme to Svilengrad | 758.57 mi (1,220.81 km) |
| Castel San Pietro Terme to Svishtov | 685.45 mi (1,103.13 km) |
| Castel San Pietro Terme to Targovishte | 750.86 mi (1,208.39 km) |
| Castel San Pietro Terme to Teteven | 641.56 mi (1,032.49 km) |
| Castel San Pietro Terme to Troyan | 664.24 mi (1,068.99 km) |
| Castel San Pietro Terme to Tryavna | 703.07 mi (1,131.48 km) |
| Castel San Pietro Terme to Tutrakan | 743.69 mi (1,196.86 km) |
| Castel San Pietro Terme to Varna | 817.13 mi (1,315.05 km) |
