The Izu Islands are a volcanic chain south of the Japanese mainland, warmed year-round by the Kuroshio Current. That current carries warm water and plankton through the chain, keeping temperatures mild even in winter and supporting the mix of temperate and tropical species that makes the islands distinctive. Sites span wall, drift, cave, drop-off, reef, and artificial reef terrain, with most dives sitting in the shallow-to-mid range. Scalloped hammerhead, green and loggerhead sea turtles, zebra bullhead shark, bobtail squid, and various nudibranchs are recorded here. Boat schedules can be disrupted by rough weather, so flexibility helps when planning a trip.
Monthly water temperature across Izu Islands's sites, from satellite sea-surface data corrected for depth. The band shows the site-to-site spread.
Water temperatures follow a clear seasonal curve, coldest from late winter through early spring and peaking in late summer. A thicker wetsuit is worthwhile from winter through spring, while a thinner suit or shorty suits mid-summer. The warmest months also tend to bring the best conditions for drift dives at exposed sites such as Zenisu seamount.
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Water temperature around Izu Islands ranges from about 20°C in January to 28°C in August, based on satellite sea-temperature data for its dive sites.
In the warm season (about 28°C) a rash guard or 3mm shorty is comfortable in Izu Islands; in the coldest months (about 20°C) step up to a 5mm suit.
Fin maps 9 sites in Izu Islands (8 scuba diving sites and 1 snorkelling spots, with some suited to both).
2 more sites to explore
