Diving the Catalina Islands, Guanacaste

The islands

The Catalina Islands, usually just called the Catalinas, are a string of bare, rocky islets off the northern Guanacaste coast, west of Playa Flamingo, Potrero and Playa Grande. Nobody lives on them, and from the beach they look like a few dark rocks on the horizon. Underwater, they're one of the busiest spots on Costa Rica's Pacific coast.

The islands sit where currents and seasonal upwelling bring cool, food-rich water to the surface. That's what feeds the plankton, the schools of fish and the big animals that follow them. Costa Rica's tourism board calls the Catalinas and the Bat Islands farther north the 2 most famous long-range dive sites in Guanacaste. Divers often lump them together as "Cats and Bats", but they're very different trips.

Giant mantas

The Catalinas are best known for giant oceanic manta rays, which can measure several meters from wingtip to wingtip. Costa Rica's tourism board says they gather here from January to April, and Misión Tiburón, a Costa Rican shark and ray research group, calls the islands the country's most important gathering site for oceanic mantas. The giant manta is listed as endangered, which is one reason those researchers want the area formally protected.

Mantas are never guaranteed, even in season. When they don't show, the Catalinas are still a strong dive.

What else you'll see

Expect large schools of reef fish, and often devil rays, spotted eagle rays, bullseye rays and stingrays. White-tip reef sharks are common, turtles are regular visitors (the nesting beach at Playa Grande is close by), and moray eels hide in the rocks. Humpback whales pass through in season, and whale sharks turn up now and then.

Above water, keep an eye out on the surface interval. Schools of devil rays sometimes leap clear of the water and land with a slap, which is a sight on its own.

Conditions and who it suits

The Catalinas are open-water sites with no beach to swim back to, and conditions change quickly. Dive shops put visibility at about 15 to 80 feet, often better than the coast nearer town but rarely gin-clear. The water is coolest in the dry season, especially January and February, when upwelling can push thermoclines up and you'll want a thicker wetsuit. Currents vary with the site, the tide and the wind, and are sometimes strong.

Most sites suit certified divers with some experience who are comfortable with current. Shops usually choose sites on the day to match the group and the conditions. Brand-new divers do better on the local sites near Playas del Coco or Flamingo first.

Getting there

Dive shops run Catalinas trips from Playas del Coco, Playa Ocotal, Playa Flamingo, Potrero and Tamarindo. From Flamingo and Potrero the islands are close; from Coco the run is longer, though fast boats make it in well under an hour. Rocket Frog Divers in Playas del Coco runs them all year. Trips are usually 2 dives with a surface interval on the boat.

Snorkeling trips also visit the Catalinas, mostly on sailing catamarans from Flamingo and Potrero, though snorkelers see far less than divers.

If you're in the area to fish, Playa Flamingo is a natural base for both: see our guide to Playa Flamingo.

Tips for the day

• Dress for cool water. Early in the year, a 5 mm wetsuit or a hood is worth having for the colder layers. Later in the year, a 3 mm suit is usually enough.
• Give mantas space. Don't chase or touch them. Stay low and still and let them come to you; a relaxed manta often circles back for another look.
• Watch your air and the current. These are open-water sites, so stay close to the guide and carry a surface marker buoy if you have one.
• Book early in manta season. Trips depend on the weather and on enough divers signing up, so tell the shop which day you'd like as soon as you can.
• Bring seasickness tablets if you need them. The ride can be bumpy when the wind is up.

Learn more

Our sister site scuba.cr covers the Catalinas' individual dive sites.