if you visit belize, you may visit Cozumel as well...both activities as well as snuba and scuba diving are available in Cozumel....and the operators are probably a little more professional an safe than in Belize...
I don't recall hearing about this in Belize. I snorkled with sting rays there with a private company called Coral Breeze limited. You can also go see Mayan ruins in Xuantunich which look quite impressive. Or you can go Cave tubing here it's one of the few places on earth you can do this my friends gave it great reviews. To get some ideas why not go to You Tube dot com and type in Belize so you can see other peoples excursions here. I would not suggest the Belize city tour or Sights and Sounds of Belize people did not give these good reviews. Tons of water sport type things should be availible here and the snorkling is excellent! Just remember you need to be on one of the Cays or small islands Belize city has no beach. Hope this helps.
Carnival Mardi Gras 1987 (Bahamas)
Carnival Legend 2005 (Exotic Western Caribbean)
Costa Mediterrenia 2005 (Eastern Caribbean)
Carnival Pride October 2006 (Mexican Rivera)
Carnival Legend 2007 (Western Caribbean)
Carnival Glory 2009 Western Caribbean
Carnival Liberty 2011 Eastern Caribbean
Norwegian Spirit 2011 Western Caribbean
Carnival Miracle 2012 Southern Caribbean
Carnival Breeze 2013 Exotic Eastern Caribbean
Carnival Valor 2014 Southern Caribbean