| Bilbao to Karlovo | 1,396.61 mi (2,247.63 km) |
| Bilbao to Karnobat | 1,505.11 mi (2,422.24 km) |
| Bilbao to Kavarna | 1,561.30 mi (2,512.67 km) |
| Bilbao to Kazanlak | 1,426.52 mi (2,295.76 km) |
| Bilbao to Knezha | 1,350.38 mi (2,173.23 km) |
| Bilbao to Kostinbrod | 1,315.08 mi (2,116.41 km) |
| Bilbao to Kozloduy | 1,330.27 mi (2,140.86 km) |
| Bilbao to Kyustendil | 1,295.45 mi (2,084.82 km) |
| Bilbao to Levski | 1,403.86 mi (2,259.29 km) |
| Bilbao to Lom | 1,305.38 mi (2,100.80 km) |
| Bilbao to Lovech | 1,385.90 mi (2,230.40 km) |
| Bilbao to Lukovit | 1,357.80 mi (2,185.17 km) |
| Bilbao to Lyaskovets | 1,435.95 mi (2,310.94 km) |
| Bilbao to Mezdra | 1,335.18 mi (2,148.76 km) |
| Bilbao to Momchilgrad | 1,444.05 mi (2,323.97 km) |
