In Belize, you HAVE to do the Cave Tubing Excursion. This is a must see, Several options:
1. Book with Carnival or
2. There is a company xstreamcavetubing. At this website: .Extreme Cave Tubing
3. Do it all on your own.
I have heard raves about the 'extreme' tubing company plus they are approx $35pp cheaper than Carnival. Here is the draw-back....if for some reason, the excursion is canceled, ie; weather or what have you, Carnival will refund your monies. I'm not sure of the other's policy
In Roatan, I plan on doing the jungle canopy tour. This looks excellent.
Costa Maya, I have no idea. Probably just staying on the ship.
I stumbled on a website: Valor Valor cruise
that is outstanding. This guy, Jason, documents all happenings in their cruises and are a joy to watch.
Hope I was able to help Take care and looking forward to talking more.