There is snorkelling and diving available, and long stretches of sandy beaches which are perfect for walking and relaxing after a hectic day.
Visit some ruins, Tulúm is just a 45-minute drive south of Playa. Aside from its unusual late Mayan architecture, it offers possibly the most appealing setting for any ruins, as it is located on a palm-fringed, white-sand beach, where you can even go for a swim within the ancient walls.
Just off the coast is the island of Cozumel, renowned for its world-class diving. Take the ferry from Playa del Carmen (30 to 75 minutes depending on the boat) across the turquoise waters and explore the towns and the reefs of the island.