The blaze, which police think was caused by a discarded cigarette, tore through more than 400 hectares (about 1,000 acres) of forest and scrubland on the edge of the Cap de Creus natural park, a popular tourist area.
"We're trying to bring the fire under control at the moment using six aircraft, which are pouring water onto the flames and 90 fire crews on the ground," said Sergi Palacios from the Catalan regional government's fire service.