There are several nice snorkelling areas nearby. Beware at all locations if the sea is rough.
At the Oasis in Los Gigantes there are steps into the sea.
The rock pool area in crab island.
Off the small beach at the harbour in Puerto Santiago.
The rocks either side of Playa arena beach.
There are several places along Punta Blanca where entry and exit is possible.
The beach/harbour at Alcala. Turtles are often seen here.
Between San Juan and Fonsalia is also very nice.