| Middlesbrough to Karlovo | 1,434.07 mi (2,307.91 km) |
| Middlesbrough to Karnobat | 1,514.89 mi (2,437.98 km) |
| Middlesbrough to Kavarna | 1,529.05 mi (2,460.77 km) |
| Middlesbrough to Kazanlak | 1,457.06 mi (2,344.91 km) |
| Middlesbrough to Knezha | 1,366.83 mi (2,199.70 km) |
| Middlesbrough to Kostinbrod | 1,368.11 mi (2,201.76 km) |
| Middlesbrough to Kozloduy | 1,340.69 mi (2,157.64 km) |
| Middlesbrough to Kyustendil | 1,375.47 mi (2,213.60 km) |
| Middlesbrough to Levski | 1,411.80 mi (2,272.07 km) |
| Middlesbrough to Lom | 1,320.54 mi (2,125.21 km) |
| Middlesbrough to Lovech | 1,407.35 mi (2,264.91 km) |
| Middlesbrough to Lukovit | 1,384.07 mi (2,227.45 km) |
| Middlesbrough to Lyaskovets | 1,445.89 mi (2,326.93 km) |
| Middlesbrough to Mezdra | 1,369.45 mi (2,203.92 km) |
| Middlesbrough to Momchilgrad | 1,510.37 mi (2,430.70 km) |
