Avilés is a town in Asturias, Spain. Avilés is, along with Oviedo and Gijón, one of the main cities in the Principality of Asturias. The town occupie…Avilés is a town in Asturias, Spain. Avilés is, along with Oviedo and Gijón, one of the main cities in the Principality of Asturias. The town occupies the flattest land in the municipality, partially in a land that belonged to the sea, surrounded by small promontories, all of them having an altitude of less than 140 metres. Situated in the Avilés estuary, in the Northern Central area of the Asturian coast, west of Peñas Cape, is its national seaport.