Puerto Rico offers top-notch snorkeling even though freshwater run-offs from tropical outbursts feeding into the sea can momentarily cloud the ocean's waters. In most places, when conditions are right, visibility extends from 50 to 75 feet (15-23m).
One of the best ways to experience this wonderful sport, even if you are staying in San Juan, is to take one of the day trips on one of the several luxury catamarans plying the waters off the coast of Fajardo, which make for some of the finest snorkeling in the Caribbean. They usually anchor on the beach of a small cay for lunch and some sunbathing and swimming. Transportation from San Juan area hotels is often provided. It's worth the trip even if you don't want to snorkel.
- Mona Island: This remote island off the west coast of Puerto Rico also offers the best snorkeling possibilities. The reefs here, the most pristine in Puerto Rico, are home to a wide variety of rainbow-hued fish, turtles, octopuses, moray eels, rays, puffers, and clownfish: the single largest concentration of reef fish life in Puerto Rico. You must bring your snorkeling equipment to the island, however, as there are no rentals available once you are here.
- Caja de Muertos: The best snorkeling off the coast of Ponce is on the uninhabited coast island of Caja de Muertos (Coffin Island). This island got its name from an 18th-century French writer who noted that the island's shape resembled a cadaver in a coffin. Over the years there have been fanciful legends about the island, including tales of necrophilia, star-crossed lovers, and, of course, piracy. Several outfits will take you to this remote spot for a full day's outing, with plenty of snorkeling.
- La Paguera: The reefs surrounding the offshore cays just off La Paguera in southwest Puerto Rico are another fine spot for snorkeling. Several boat operators right in town will either rent you a boat with a guide or drop you off on one of the islands and return at a prearranged timed.
- Fajardo: On the eastern coast of Puerto Rico, the clear waters along the beachfront are the best on mainland Puerto Rico for snorkeling. The best beaches here for snorkeling are walking distance from the Seven Seas public beach: Playa Convento. The snorkeling at Las Cabezas de San Juan nature refuge is also spectacular. (WARNING: Playa Escondida which is nearby is often recommended for snorkeling but is extremely dangerous due to tidal activity, do not snorkel, surf, or swim there.)