Niihau lies in the Pacific Ocean off the western coast of Kauai, and its surrounding waters are accessible only by boat charter. The island itself is privately owned and entry is restricted, which has left the marine environment largely undisturbed. The six sites in our database span an exceptional range of terrain: reef slopes, walls, caverns, pinnacles, and a long sunken barrier reef called Mana Crack that runs for eleven miles and is conducted as a live-boat dive. Depths reach seventy metres at Lehua Crater. Strong currents are common across multiple sites, and most require advanced certification. Water temperatures are warm throughout the year, with the calmest and most accessible conditions generally between late spring and early autumn.
Monthly water temperature across Niihau's sites, from satellite sea-surface data corrected for depth. The band shows the site-to-site spread.
Water stays warm year-round, with the coolest months in late winter and early spring and the warmest from mid-summer through autumn. Calmer sea states make the offshore crossing most reliable from late spring through early autumn, which aligns with the generally recommended dive season. Currents are a significant factor at most sites regardless of season.
2 operators
Water temperature around Niihau ranges from about 23°C in March to 27°C in September, based on satellite sea-temperature data for its dive sites.
In the warm season (about 27°C) a rash guard or 3mm shorty is comfortable in Niihau; in the coldest months (about 23°C) step up to a 3mm full suit.
Fin maps 6 sites in Niihau (6 scuba diving sites).
2 more sites to explore
