Costa Rica has a lot of ocean front and as you’d expect some excellent diving. However there are some limitations especially for beginners. Most of the really good locations are off-shore and in relatively deep water with strong currents.
The best dive site in Costa Rica is recognized as one of the top five in the entire world but it’s way off-shore (about 500 km) at Cocos island. It takes almost 24 hours to motor out to this amazing island north of the Galapagos chain and special permission is required to dive with the huge schools of hammerhead sharks and other pelagic life found there.
Most visitors pay between $3,000 and $7,000 per person for multi-day live aboard (tourists are not allowed on the uninhabited island) dive trips.
The bat (Murcialago) islands on the northern Guanacaste and Caño island off the Osa peninsula are within 30 minutes of the coast in a motorboat and popular with divers.
There are a very few places where you can just rent or bring snorkel gear and walk out to reefs and rock formations from the beach. The spots we recommend are mostly protected by points, out-croppings or small islands. However, they still have waves and currents and there is nowhere in Costa Rica where you’ll find the sort of glassy calm clear water like on the Caribbean islands.
Our favorite spot is Playa San Josecito south of Drake bay on the Osa Peninsula. There are several small islands and a large rocky point that take the brunt of the Pacific surge making the large bay relatively calm and the setting onshore couldn’t be more amazing. Most snorkelers here are also visiting Corcovado National Park a few km to the south and the area offers a number of remote, rustic eco-lodges.
Offshore in the same vicinity is Caño Island which is another personal favorite. Boat tours are offered from the southern Pacific beaches of Manuel Antonio, Dominical and Uvita as well as Drake and visitors are frequently treated to humpback whale or porpoise sightings during the ride.
The southern Caribbean and Cahuita National Park are home to Costa Rica’s largest coral reefs and most famous snorkeling. The snorkeling is best in September and October when the Caribbean is calmest and the weather in the region clear and sunny. Unfortunately the coral that was struggling due to pesticide and fertilizer runoff from the nearby banana plantations was mostly killed in 1992 when an earthquake raised the sea floor 3 meters and exposed the reefs to sun and drying.
In an effort to protect the few remaining live polyps no one is allowed to snorkel without a guide.
Snorkeling is often included as an option on sailing or catamaran tours to Turtle Island (near the southern end of Nicoya but usually visited from Jacó, Manuel Antonio or even San José), or from Tamarindo.
Coral reefs all over the world have been decimated by rising water temperatures. Early in 2016 reports on the health of the Great Barrier Reef in Australia indicated that well over one third is completely dead. Nearly all of the live coral is severely bleached and would take a decade to recover in the extremely unlikely event that water temperatures returned to normal.
Costa Rica’s coral has not fared any better.