Direct answer
Mamita's Beach Club (Coco Beach side) for the polished beach-club day. Punta Esmeralda (north end) for the free public-beach + cenote combo. Playa Fundadores (centro) for the most accessible. North of Selvamar is the cleanest sargassum-wise. Skip the cruise-pier beachfront — crowded and rough.
Playa's beach runs the full length of the city — every point along it is legally public. The cleanest, lowest-sargassum section is Coco Beach (north of the ferry). Mamita's is the polished beach-club default. Punta Esmeralda combines a free public beach with a freshwater cenote that meets the ocean. Playa Fundadores is the centro access point. Avoid the cruise-pier beach south of 5th and Constituyentes.
