| Upminster to Mangualde | 847.34 mi (1,363.66 km) |
| Upminster to Marco de Canavezes | 819.75 mi (1,319.26 km) |
| Upminster to Marinha Grande | 926.83 mi (1,491.59 km) |
| Upminster to Massama | 996.78 mi (1,604.16 km) |
| Upminster to Matosinhos | 832.69 mi (1,340.09 km) |
| Upminster to Mealhada | 876.35 mi (1,410.34 km) |
| Upminster to Melgaco | 765.27 mi (1,231.59 km) |
| Upminster to Melres | 832.75 mi (1,340.19 km) |
| Upminster to Mira | 879.71 mi (1,415.76 km) |
| Upminster to Miranda do Corvo | 891.50 mi (1,434.72 km) |
| Upminster to Mirandela | 779.44 mi (1,254.38 km) |
| Upminster to Mogadouro | 779.47 mi (1,254.44 km) |
| Upminster to Moimenta da Beira | 820.52 mi (1,320.49 km) |
| Upminster to Moita | 997.13 mi (1,604.72 km) |
| Upminster to Moncao | 773.18 mi (1,244.31 km) |
