Costa Maya -- either do a ruins tour of Chacchoben with The Native Choice, or take a cab to Mahahual (a village on the seashore) and enjoy the malecon, beach, swimming, and the food at the beach restaurants. The cabs cost $3 to the beach per person, $2 to return to the ship per person. Lots of tables, chairs, umbrellas there, and the expectation is that you will purchase food and beverages. Very nice, clean beach and clear water.
The ruins tour is very good too. A van ride 45 minutes or so to the site, about 1.5 hrs at the site. You can add a trip to a lagoon or a lunch with a Mayan family. Check their website.
Is your Honduras stop Roatan? Lots of private operators on Roatan who can customize a day for you. The water is great.