We went to 5 different beaches when we visited Puerto Rico. This had the most beautiful aquatic life. We spent hours snorkeling at Steps Beach, which is a part of the Tres Palmas Marine Reserve. You can rent snorkel gear for $15-$20 for the day, or you can just buy your own and bring it with you.
There are not many people to disturb you as you swim about looking at fish. We saw corals and every color fish imaginable. The waves were a little active when we were there, but it didn't affect our snorkeling.
Con: The only downside is that you must be careful not to get bitten by ants in the shade! Most of the trees that line the shore have small fruit that falls onto the sand and begins to rot. The ants love this and congregate under the same shady spot under the trees that you would like to set up your chair under. We chose to drag our chairs into the sun rather than get bitten.
If you own or manage Tres Palmas Marine Reserve, register now for free tools to enhance your listing, attract new reviews, and respond to reviewers.