Just returned yesterday (sigh .....) and just wanted to share what we found was the best place to snorkel at Xel-Ha. Everyone tells you to go by the floating bridge which does have big fish, but its someone cloudy because of all the people and that's where they do the sea trek. What we found by chance was that the best snorkeling was by the manatee. We wanted to see them underwater so we went back to get our snorkel gear and we found hundreds of fish (and very few people) there. On the manatee side there is a nice inlet with lots of fish. And on the other side there are lots of coral formations that you can weave through. Just look out for the large barracuda (about 4 feet long). We spent about 2 hours in this location. If you have any other questions, I would be happy to answer if I can.