The weather wasn't that great but we had planned to take a taxi to Chankanaab Park for the day so we decided to do it anyway and it was well worth it. The beaches were closed due to high winds but the park was still a great time. We had a nice lunch in their restauarant on site. We didn't buy tickets through Carnival and instead purchased them at the park upon arrival. We even found a $2 off coupon on line which they honored. There was a wonderful tequila tasting shop which shouldn't be missed.
We purchased a snorkeling excursion through Carnival which including snorkeling and some beach time on Rendevous Caye. Since this was a tender port, this was absolutely the right way to go. The tender rides to shore were 30 minutes and the best snorkeling sites were 30 minutes or more the other way! The excursion took us directly from the ship allowing for more time on the small island as well as a more relaxed trip back. When I say the island was small, that is really an understatement - it cannot be more than 1.5 acres in total size - but we were the only group there so there was plenty of room for everyone. The equipment they supplied for snorkeling was great although they were a little disorganized in leading us out but the trip was still lots of fun.
This was the best stop, mostly due to the amazing excursion we booked directly through Island Marketing. They arrange for us to go out on a 31' caramaran which said they would take 10 passengers. When we got there, it was only the 6 of us so we had the whole trip to ourselves! The ship was captained by an Italian man named Roger (his company is called Roger's Cat-Cruises and I would HIGHLY recommend him). He took us into a beautiful cover behind the reef for amazing snorkeling and then swimming. I expected the trip to be 1.5 hours but we were out for 3 hours and it was the highlight of the trip. Beware of the roads on the island though, lots of pot holes and cliffs on both ends!