It's a little far, about 150 KM from Cancun, but it's something I would recommend.
Not only you will see the beauty of hundreds of flamingos flying over the waters, but you will face a sanctuary of wildlife and marvelous sights. And it will be easy to add the visit to the mandatory trip to Chichen Itza.
Aquaworld ,where we hired a speedboat and went snorkeling,great day out.Aquaworld do a choice of trips and days out.We choose a 3 hour speedboat trip.I did enjoy it,but the sea was very rough and i still have bruises on my legs now.We booked the trip through our rep and paid about38$ which was ok as it was the same price at Aquatours too.We raced a speedboat over the lagoon out to the Caribbean sea and then snorkeled.It was amazing and the fish were huge.
This is also a not to be missed trip,but do remember that the sea is very rough and you will get drenched.The sea tends to be rougher in the afternoon,so go in the morning if you want to avoid it.Phone number for Aquatours is -(98)830400
Here is Aquaworlds web page.........'http://www.aquaworld.com.mx/