Hyatt Cerromar and Hyatt Dorado in Puerto Rico have snorkeling at the beach, fish and coral. I used to get sent there on business trips, and would snorkel there before and after work. Way cool snorkeling. The Cerromar has a river pool in addition to the regular pools - way cool to float around the river pool with a drink
The Marriott in Curacao also has snorkeling at the beach, very good fish and coral.