The town beach at Baiona sits right at the edge of the old quarter, a compact strip of sand sheltered by the headland from the worst Atlantic swells. The water is cold — this is Galicia, not Andalusia — but the beach is swimmable in summer and has a pleasant backdrop of old stone buildings.
For better beaches with more sand and fewer crowds, head south along the coast road toward Oia and Mougás. A car makes the difference here; the coastal road passes a string of unspoilt coves and bays, most of them empty outside August. The Cíes Islands, a national park archipelago visible from Baiona, have exceptional beaches but access requires a ferry from Vigo.