| Castel San Pietro Terme to Popovo | 732.27 mi (1,178.47 km) |
| Castel San Pietro Terme to Provadia | 793.73 mi (1,277.38 km) |
| Castel San Pietro Terme to Radnevo | 734.42 mi (1,181.94 km) |
| Castel San Pietro Terme to Radomir | 583.55 mi (939.14 km) |
| Castel San Pietro Terme to Rakitovo | 650.70 mi (1,047.21 km) |
| Castel San Pietro Terme to Rakovski | 687.23 mi (1,105.99 km) |
| Castel San Pietro Terme to Razgrad | 744.00 mi (1,197.35 km) |
| Castel San Pietro Terme to Razlog | 623.17 mi (1,002.90 km) |
| Castel San Pietro Terme to Ruse | 713.09 mi (1,147.61 km) |
| Castel San Pietro Terme to Samokov | 617.37 mi (993.56 km) |
| Castel San Pietro Terme to Sandanski | 622.19 mi (1,001.32 km) |
| Castel San Pietro Terme to Sevlievo | 681.54 mi (1,096.84 km) |
| Castel San Pietro Terme to Shumen | 767.69 mi (1,235.48 km) |
| Castel San Pietro Terme to Silistra | 774.84 mi (1,246.99 km) |
| Castel San Pietro Terme to Sliven | 747.14 mi (1,202.40 km) |
