What are your ports of call? Stingray City in Grand Cayman was awesome. The falls in Ochos Rios also tubing down the river in Ochos Rios. In Cozumel, Chankanaub park was beautiful (beach and swim with the dolphins). Costa Maya, definately do an excursion, otherwise you just sweat in a glorified shopping center (pretty area but not much to do), unfortunately I didn't book an excursion but those who did loved it.