The Ninepin Islands are an exposed archipelago southeast of Clear Water Bay, part of the UNESCO Global Geopark and known above water for their hexagonal volcanic rock columns and sea caves. Diving here ranges from shallow reef slopes accessible to beginners through to drop-offs and caverns suited to intermediate divers. Sites span from around five to just over twenty metres, and the open-sea position means conditions depend heavily on wind and tidal state: calm days with slack tides are essential. The marine life is notably varied, with nudibranchs, frogfish, seamoths, and grouper recorded across sites such as Trio Island, East Ninepin, and Basalt Island. All access is by boat, and the journey from Sai Kung takes the better part of an hour or more.
Monthly water temperature across Ninepin Islands's sites, from satellite sea-surface data corrected for depth. The band shows the site-to-site spread.
Water temperature is coolest in January and February at around nineteen to twenty degrees, rising to twenty-nine degrees in late summer. The open position of the islands means currents can run strongly, and conditions are best on calm, low-wind days around slack water. Visibility is generally better here than at more sheltered inner sites, though it can still vary between visits.
Water temperature around Ninepin Islands ranges from about 19°C in January to 29°C in September, based on satellite sea-temperature data for its dive sites.
In the warm season (about 29°C) a rash guard or 3mm shorty is comfortable in Ninepin Islands; in the coldest months (about 19°C) step up to a 5mm suit.
Fin maps 5 sites in Ninepin Islands (5 scuba diving sites and 1 snorkelling spots, with some suited to both).
2 more sites to explore
