| Merthyr Tudful to Masanasa | 864.14 mi (1,390.71 km) |
| Merthyr Tudful to Masquefa | 748.65 mi (1,204.84 km) |
| Merthyr Tudful to Matadepera | 745.39 mi (1,199.60 km) |
| Merthyr Tudful to Mazarron | 982.45 mi (1,581.10 km) |
| Merthyr Tudful to Meco | 773.10 mi (1,244.18 km) |
| Merthyr Tudful to Medina del Campo | 725.20 mi (1,167.09 km) |
| Merthyr Tudful to Medina Sidonia | 1,062.81 mi (1,710.42 km) |
| Merthyr Tudful to Mejorada del Campo | 783.95 mi (1,261.65 km) |
| Merthyr Tudful to Meliana | 856.42 mi (1,378.28 km) |
| Merthyr Tudful to Mengibar | 951.97 mi (1,532.05 km) |
| Merthyr Tudful to Merida | 898.71 mi (1,446.33 km) |
| Merthyr Tudful to Miajadas | 879.64 mi (1,415.64 km) |
| Merthyr Tudful to Mieres | 597.25 mi (961.19 km) |
| Merthyr Tudful to Miguelturra | 883.19 mi (1,421.35 km) |
| Merthyr Tudful to Mijas | 1,048.09 mi (1,686.73 km) |
