São Martinho do Porto
The perfect horseshoe-shape bay here, 12 miles west of Alcobaça, makes this one of Portugal's prettiest beaches, lapped by calm waters that are safe for children. The ample strand—patrolled by lifeguards so long as beach cafés are open—has fine, yellow sand (cleaned daily) and areas with sunshades for rent. Much of it is lined with well-preserved dunes; at its northern end, set back from the promenade, are elegant old homes in the typical Caldas style, restaurants, and many hotels. The beach is popular with local families, so don't come in high summer if you dislike crowds. Local companies offer boating and canoeing trips. Amenities: food and drink; lifeguards; parking (no fee); toilets; water sports. Best for: sunset; swimming; walking.
