| Southend to Mangualde | 857.04 mi (1,379.28 km) |
| Southend to Marco de Canavezes | 830.18 mi (1,336.04 km) |
| Southend to Marinha Grande | 937.13 mi (1,508.16 km) |
| Southend to Massama | 1,006.85 mi (1,620.36 km) |
| Southend to Matosinhos | 843.63 mi (1,357.70 km) |
| Southend to Mealhada | 886.57 mi (1,426.79 km) |
| Southend to Melgaco | 776.44 mi (1,249.56 km) |
| Southend to Melres | 843.34 mi (1,357.23 km) |
| Southend to Mira | 890.22 mi (1,432.67 km) |
| Southend to Miranda do Corvo | 901.45 mi (1,450.74 km) |
| Southend to Mirandela | 789.10 mi (1,269.94 km) |
| Southend to Mogadouro | 788.55 mi (1,269.05 km) |
| Southend to Moimenta da Beira | 830.30 mi (1,336.24 km) |
| Southend to Moita | 1,006.90 mi (1,620.44 km) |
| Southend to Moncao | 784.52 mi (1,262.56 km) |
