Catalina Islands

The Catalinas are a group of bare volcanic rocks and pinnacles a short run offshore from Flamingo on the Guanacaste coast, and their reputation rests on rays: from December to April, when upwelling brings cold nutrient-rich water into the area, giant manta rays and mobula rays gather at the sites in numbers, along with white-tip reef sharks, turtles, eagle rays and large schools of fish. The dives are moderate rather than technical, with depths to around thirty metres and some current. Water temperature drops sharply in the season and a thicker wetsuit is needed. Snorkelling trips also run. The rocks themselves carry seabirds and are not landed on.

What you actually see

• Manta and mobula rays - the aggregations in the cold-water season.
• Reef sharks and turtles - the other regular animals on the sites.
• The pinnacles - the underwater rock formations the dives work.
• Seabirds - the colonies on the bare rocks above water.

When to go

December to April for the mantas, which follow the cold upwelling; the rest of the year has warmer, clearer water but far fewer rays. Wind in the dry season can make the crossing choppy.

Honest expectations

Manta sightings are seasonal and not guaranteed even in the window. Water is markedly colder in the manta season and thicker exposure suits are needed. Visibility varies with the upwelling. Trips cancel in wind.

Nearby

Flamingo lies east on the coast; Las Catalinas is the town of the same name onshore.