We had never been to Roatan where we did the zip line. We would recommend it as it is a short walk from the pier and consists of 11 lines of various lengths. The beach was also a short walk and crowded with two ships in port. Don't waste your money on the sky lift to get there.
We snorkeled in Belize at Anthony's Cay and the variety of fish was impressive and small guided groups very well orchestrated. We would take this snorkel trip again. We did not take the time to go into Belize City as we have been there many times before and decided just to enjoy some time on board in the spa.
We walked the 3 or so miles downtown in Cozumel to get our exercise. We took a cab back as the cost was only 4 dollars a person and we were carrying some heavy packages. We have been to Cozumel many times and there is a reason it is on almost every Western Caribbean trip.