We just did Xcaret via Disney-- went there in 2004 while staying in playa del Carmen and had a great time when it was just me and DH. Now three kids later (9, 9, almost 5) it was still fun and even bigger with so much to see and do. There is a high speed air conditioned ferry (30 minutes) that takes you from Cozumel to Playa Del Carmen then a bus to xcaret (20 min) which is an eco park. The local tour operators were fantastic and very professional. The water park has three lazy river swims - one completely underground, one in open water only and third that is half and half (which we did). Lunch is included. There is a nice beach and snorkeling lagoon with lots of fish. There is a small aquarium, tons of turtles and macaws that were rescued and being raised for release into the wild. There is also opportunity to swim with dolphins and nurse sharks which is extra but we did not do these. We only saw about a third of the park due to having to catch the ferry back to Cozumel.
