Poipu, Hawaii, United States

Sheraton Caverns

Sheraton Caverns sits about half a kilometre off the Sheraton Kauai Resort at Poipu on the south shore of Kauai, the most consistently calm and accessible coast on the island. The site consists of three large collapsed lava tubes that run roughly perpendicular to shore and connect through wide openings at depths from 9 to 18 metres. The tubes are big enough to swim through without being a true overhead environment: there is always an obvious exit and ceiling clearance. Sheraton has become Kauai's signature green sea turtle dive: at least a dozen large resident animals use the cavern walls as a cleaning station, and encounters with three to six turtles per dive are normal. Reef life on the surrounding lava rubble bottom includes white tip reef sharks resting in the side caves, ornate butterflyfish, yellow tang, scrawled filefish, octopus and the occasional Hawaiian green lionfish. Currents are typically weak; visibility ranges from 12 to 25 metres depending on swell.