Isla del Caño

Caño is an uninhabited island of about three square kilometres roughly twenty kilometres off the Osa Peninsula, protected as a biological reserve, and it is where Pacific Costa Rica has its clearest water: visibility regularly runs past twenty metres, which on this coast is exceptional, and the rock reefs around it hold white-tip reef sharks, rays, turtles and large schools of fish. Humpback whales pass through in two seasons. In the forest above are stone spheres of the Diquís culture, carried here in pre-Columbian times and evidence that the island was used ceremonially, possibly as a burial ground.

What you actually see

• The diving and snorkelling - the clearest water on the Costa Rican Pacific.
• White-tip reef sharks - resting on the sand between the rock reefs.
• Humpback whales - passing in two separate seasons.
• The stone spheres - Diquís spheres carried to the island in antiquity.

When to go

December to April has the calmest crossings and best visibility. Humpbacks pass from July to October and again from December to March, from the southern and northern populations respectively. Landing on the island is now heavily restricted, so most trips are water-based.

Honest expectations

Landing is restricted to protect the reserve and the archaeology, so for most visitors this is a boat and water trip with no time ashore. The crossing from Uvita is long and often rough. Numbers of divers are capped daily. Coral here has suffered from warming events and the reef is patchy in places.

Nearby

Drake Bay and Corcovado are on the Osa Peninsula; Uvita is on the mainland coast.