Soto del Barco, Spain offers 1 beach perfect for sunbathing, surfing, swimming, and more. Soto del Barco is known for the Castillo de San Martin, a historic castle offering scenic views of the Nalon River. The best time to travel to Soto del Barco, Spain, is from June to September, with average air temperatures around 68-77°F (20-25°C) and water temperatures around 64-70°F (18-21°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!