Chankanaab National Park is located at km 9.5 of the coastal highway. This eco-park offers snorkeling, scuba diving and Snuba, a natural spa, swimming with dolphins or manatees, a sea lion show, tropical gardens, Mayan ruin replicas, a bird sanctuary, a crocodile farm, a playground and more. It's just a 10 minute taxi ride from the cruise ship dock. If you don't feel like doing anything at all, you can do that at Chankanaab as well... just relax on the beach under a palapa or in a hammock with a bucket of beer. Don't book though the cruise line. Take a taxi to the park yourself and save a lot of money.