Galicia has over 770 beaches along its deeply indented coastline, ranging from sheltered inlets in the Rías Baixas to exposed Atlantic strands in the north. The water is cold year-round by Mediterranean standards, but in summer the Rías Baixas beaches at Sanxenxo, O Grove, and Baiona get genuinely warm and busy. The wilder beaches of the Costa da Morte and the Rías Altas are spectacular but rough — better for walking than swimming.
The Cíes Islands, accessible by ferry from Vigo, have some of the most beautiful beaches in Spain — fine white sand, clear water, and protected as part of the Atlantic Islands National Park. Numbers are capped, so book ferry tickets in advance in July and August.