| Opmeer to Marco de Canavezes | 1,004.22 mi (1,616.14 km) |
| Opmeer to Marinha Grande | 1,109.89 mi (1,786.19 km) |
| Opmeer to Massama | 1,178.08 mi (1,895.94 km) |
| Opmeer to Matosinhos | 1,020.07 mi (1,641.65 km) |
| Opmeer to Mealhada | 1,059.23 mi (1,704.67 km) |
| Opmeer to Melgaco | 954.35 mi (1,535.87 km) |
| Opmeer to Melres | 1,018.09 mi (1,638.47 km) |
| Opmeer to Mira | 1,064.30 mi (1,712.82 km) |
| Opmeer to Miranda do Corvo | 1,072.65 mi (1,726.26 km) |
| Opmeer to Mirandela | 959.56 mi (1,544.27 km) |
| Opmeer to Mogadouro | 955.96 mi (1,538.46 km) |
| Opmeer to Moimenta da Beira | 1,001.08 mi (1,611.08 km) |
| Opmeer to Moita | 1,176.55 mi (1,893.48 km) |
| Opmeer to Moncao | 963.15 mi (1,550.05 km) |
| Opmeer to Montalegre | 957.13 mi (1,540.36 km) |
