| Bilbao to Popovo | 1,458.53 mi (2,347.28 km) |
| Bilbao to Provadia | 1,519.99 mi (2,446.19 km) |
| Bilbao to Radnevo | 1,457.65 mi (2,345.86 km) |
| Bilbao to Radomir | 1,305.17 mi (2,100.46 km) |
| Bilbao to Rakitovo | 1,369.95 mi (2,204.72 km) |
| Bilbao to Rakovski | 1,409.50 mi (2,268.37 km) |
| Bilbao to Razgrad | 1,470.41 mi (2,366.40 km) |
| Bilbao to Razlog | 1,340.60 mi (2,157.49 km) |
| Bilbao to Ruse | 1,439.50 mi (2,316.65 km) |
| Bilbao to Samokov | 1,338.33 mi (2,153.83 km) |
| Bilbao to Sandanski | 1,336.40 mi (2,150.72 km) |
| Bilbao to Sevlievo | 1,406.91 mi (2,264.20 km) |
| Bilbao to Shumen | 1,493.98 mi (2,404.33 km) |
| Bilbao to Silistra | 1,500.79 mi (2,415.29 km) |
| Bilbao to Sliven | 1,472.07 mi (2,369.07 km) |
