| Merthyr Tudful to Miranda de Ebro | 626.31 mi (1,007.95 km) |
| Merthyr Tudful to Mislata | 859.46 mi (1,383.16 km) |
| Merthyr Tudful to Moana | 700.41 mi (1,127.19 km) |
| Merthyr Tudful to Moguer | 1,013.80 mi (1,631.55 km) |
| Merthyr Tudful to Molina de Segura | 951.57 mi (1,531.40 km) |
| Merthyr Tudful to Molins de Rey | 757.72 mi (1,219.44 km) |
| Merthyr Tudful to Mollerusa | 727.07 mi (1,170.11 km) |
| Merthyr Tudful to Mollet | 752.89 mi (1,211.66 km) |
| Merthyr Tudful to Moncada | 755.72 mi (1,216.21 km) |
| Merthyr Tudful to Moncada | 854.79 mi (1,375.65 km) |
| Merthyr Tudful to Monforte de Lemos | 666.23 mi (1,072.19 km) |
| Merthyr Tudful to Monforte del Cid | 932.18 mi (1,500.20 km) |
| Merthyr Tudful to Mongat | 758.53 mi (1,220.74 km) |
| Merthyr Tudful to Monovar | 927.52 mi (1,492.70 km) |
| Merthyr Tudful to Monserrat | 866.06 mi (1,393.78 km) |
