Gulf of Papagayo & Playas del Coco

Diving here is a half-day affair. Boats leave Playas del Coco at 8:00 and are back around 12:30, with two dives at two different sites and the option of a third tank. Every site in the local pool, more than 15 of them around islands, rocky outcrops and pinnacles, lies 10 to 20 minutes from the beach. Deep Blue Diving and Summer-Salt Dive Center both run these trips from Coco, with two or three tanks on offer.

The terrain is mostly volcanic rock: low islands, rock fingers running into the deep, walls dropping to sand channels and pinnacles rising almost to the surface. Whitetip reef sharks rest in caves at Tortuga and Virador, stingrays lie on the sand at Tiburones, and eagle ray schools pass Cabeza de Mono. Meros holds nudibranchs, grunt schools and the giant groupers it is named for, Punta Argentina has frogfish, and at Sorpresa fish spiral from the floor to the surface past large moray eels.

Most sites are rated easy and the depths sit between 5 and 30 m, so newly certified divers fit in well; the nutrient-rich water keeps visibility between 5 and 23 m (15 to 75 ft). Divers after a bigger day in stronger water can book the Bat Islands, a separate 8-hour trip from the same beach, a little over an hour each way by fast boat, where strong currents and large waves keep the diving for experienced divers.

Temperature is the thing to plan around. The water averages 26 °C through the year and peaks near 30 °C from June to August, but from December to March it can drop to 20 °C, and cold water sits below a thermocline between 15 and 30 m, so the deeper part of a dive can feel much cooler than the shallows. Current is usually mild, though it runs often at Tiburones and Sorpresa is an advanced dive.