Located in the northwest of the Iberian Peninsula, it sits on the southern shore of an inlet of the Atlantic Ocean, the Ria de Vigo, the southernmost of the so-called Rías Baixas.

The municipality is the most populous in Galicia. The area of the municipality includes the Cíes Islands, part of the Atlantic Islands of Galicia National Park.

Close to the Portugal–Spain border, Vigo is part of the Galicia–North Portugal Euroregion.