Izu Seven Islands

Strung out across the warm Kuroshio Current south of Tokyo, the Izu Seven Islands (Izu Shichito) are the city's wildest dive escape. Each speck of volcanic rock has its own underwater personality, from beginner-friendly white-sand bays to current-swept pinnacles where pelagics gather, yet most are only an overnight ferry or short flight from the capital. This is a practical, island-by-island guide. For the wider region, see our Izu Shoto overview, and check ferry and flight routes on our maps.

The islands

Oshima

The largest and closest island, Oshima is the gateway, crowned by the still-smoking Mihara volcano. It is the easy yes for a first island trip: a jet ferry from Tokyo's Takeshiba Pier runs in roughly two hours, from Atami in about 45 minutes, with short flights too. Underwater, lava-sculpted arches and crevices draped in soft coral hold reliable visibility and a generous mix of temperate and tropical fish. A sound all-rounder for any level.

Toshima

Tiny, steep and gloriously quiet, Toshima is a single conical stratovolcano about 25 km south of Oshima, ringed by camellia groves. Diving here is intimate and low-key, with very good odds of meeting sea turtles, and resident dolphins are sometimes encountered offshore. With only a small harbour, it suits travellers who want untouched water and a slower pace; access is by ferry from Tokyo, weather permitting.

Niijima

Famous topside for its surf beaches, pale Koga-stone cliffs and free seaside hot springs, Niijima pairs laid-back island culture with sheltered coves and reef diving. The Kuroshio keeps the water lively with seasonal schools and warm-current visitors, and relaxed shore entries make it a comfortable base. Reached by overnight large ferry or by faster jet ferry from Takeshiba in the warmer months.

Shikinejima

A short local boat hop from Niijima, little Shikinejima is barely 12 km around but blessed with a deeply indented, wind-sheltered coastline that gives it some of the calmest, most beginner-friendly beach diving in the chain. Its signature quirk is a submarine hot spring, where warm bubbles rise from the seabed and turtles sometimes doze in the heated sand. A gentle, characterful stop for new divers and snorkellers.

Kozushima

Near the centre of the chain and squarely in the Kuroshio's path, Kozushima is the island for crystal-clear water. The calmer western side, with white-sand seabeds around popular Akasaki, suits training, try-dives and photography, while exposed shores offer current-charged reefscapes for advanced divers. Expect sea turtles, amberjack, rainbow runners and schools of striped boarfish. Reached by jet ferry from Tokyo in about four hours, or by air.

Miyakejima

Miyakejima is the great comeback story of the chain. The 2000 eruption of Mount Oyama emptied the island for five years, and returning divers found the water transformed: lava flows had poured into the sea, leaving dramatic arches and drop-offs while nature reclaimed the reefs. Today the subtropical life riding the Kuroshio is superb, with big schools, migratory fish and table corals, across everything from easy shore dives to dynamic boat sites. Access is by overnight ferry or a short flight from Chofu.

Mikurajima

Steep, forested Mikurajima is all about wild dolphins. Around 150 Indo-Pacific bottlenose dolphins live in its waters, and from spring to late autumn you can swim alongside them, but only by snorkel and free-diving; scuba is not permitted, and outings run under licensed guides as the whole island is protected parkland. A bucket-list encounter rather than a tank-diving destination. Reach it by overnight ferry from Tokyo (about seven and a half hours) or by helicopter from Miyakejima or Hachijojima.

Tip: for the dolphin swim at Mikurajima you need to be a confident snorkeller or freediver, comfortable in open water with no fins-down rest stop, since scuba is banned and touching the animals is strictly forbidden.

Hachijojima

The southernmost of the main group and the trophy island for big-fish hunters, Hachijojima sits about 290 km south of Tokyo where temperate and subtropical worlds collide. More than 700 fish species have been recorded, including endemics like the wrought-iron butterflyfish, alongside amberjack, dogtooth tuna and seasonal hammerhead and thresher sharks on the summer and autumn current. The legendary shore site Nazumado rewards divers who handle its tidal flow with exceptional fish density. A short flight from Haneda or an overnight ferry gets you there; this island favours experienced divers.

Plan your dive

• Best season: roughly July to November for warm water and big pelagics; spring and autumn also dive well, and winter brings the clearest visibility.
• Water temperature: around 26 C at its August to September peak, dropping to about 15 C in February and March.
• Visibility: generally good year-round thanks to the Kuroshio, often best in cooler months offshore.
• Level: Shikinejima, Kozushima's west coast and Oshima suit beginners; Hachijojima, Miyakejima and current-swept sites reward advanced divers.
• Getting there: overnight and seasonal jet ferries from Tokyo's Takeshiba Pier, jet ferries from Atami to Oshima, plus flights to Oshima, Miyakejima and Hachijojima.

Ready to plan? Browse every Japanese dive region on our destinations page, or get in touch via contact.