The Camino de la Costa or Coastal Route, inscribed on the UNESCO World Heritage List in July 2015, is one of the earliest pilgrimage routes to Santiago, and this route was the way by which the veneration of the remains of St James the Greater spread during the 9th century. Key to this expansion was not only the sea, through the development of maritime trade, but the reinstatement of old roads running close to the coast dating from Roman times and early medieval period. There is documentary evidence of the existence of the Camino in the 9th and 10th centuries. Records also show that large numbers of pilgrims landed at ports such as Castro Urdiales, Laredo, Santander and San Vicente de la Barquera in the 12th and 13th centuries.
This is a difficult route, given the rugged terrain, but the landscape is particularly rewarding. It features a succession of irregular highland plains, coastal mountain ranges, inlets and narrow coastal valleys, which forced pilgrims in the past to combine overland and sea journeys, and even to resort to sailing along the coast.