Japan · Bonin Islands

Ogasawara

Warm-season access lines up with dolphin, pelagic and blue-water diving.

The Ogasawara (Bonin) Islands are 1,000km south of Tokyo — a UNESCO World Heritage natural site reached only by a 24-hour ferry from Tokyo Bay. Whale sharks, humpback whales (in season), dolphins, hammerheads, and Japanese marine life on volcanic walls.

Good season

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

April–November is peak. Humpbacks pass through February–April. Dolphins year-round.

Trip duration

5–7 nights, plus 48h round-trip ferry.

Dive style

Wall and pelagic diving; some current.

Dive level

Advanced + 50 dives.

Reef health

What you’ll actually find
Holding steady

One of the few reefs whose live coral has held up over the last decade. Plan with confidence.

Coral reef health

How is this calculated?
A decade ago
Survey 2014
44%
Today
Survey 2024
44%

Heat stress right now

No stress

No abnormal heat right now. Corals stay coloured.

NOAA Coral Reef Watch · updated May 2026 · 0 °C-week heat dose

What to expect on a dive

Remote Japanese archipelago, oceanic, low diver pressure. Cetacean encounters seasonally.

Sources, methodology, and the raw numbers

Raw observed numbers

  • Coral cover: 44% (survey Sep 2024, Local Pacific reef survey)
  • Bleached: 6%
  • Recent mortality: 2%
  • Western Pacific refugium — observed condition reflects the stable regional pattern.

Raw thermal numbers

  • NOAA CRW alert level: No stress
  • Degree Heating Weeks: 0 °C-wk
  • SST anomaly: +0.6 °C

How we summarise this

Observed coral cover, bleaching, and mortality come from named in-situ surveys with a stated date and method — they describe one snapshot of one reef and do not extrapolate to neighbouring sites. Current thermal stress is satellite-derived from NOAA Coral Reef Watch at ~5 km resolution; it indicates risk, not observed coral damage. We deliberately separate observed condition, current thermal stress, and projection — and we never publish a projection without a documented model and uncertainty.

Sources

Reef condition changes year to year. If you visit, consider supporting responsible-travel and conservation operators on the ground.

Pressure on this reef

Protection · fishing · what you can do

Protected-area status

Multi-use MPA

Inside a designated MPA that permits regulated fishing and other uses. Worth checking which zones at this location are no-take.

Fishing pressure

High fishing pressure

Dominant pressures

  • fisheries pressure
  • coastal development

1 Green Fins-verified operator known at this location.

What you can do

Ogasawara Islands are UNESCO World Heritage. Japanese reefs are at the cool edge of coral range. Most protection is via prefectural fishing co-op rules rather than formal MPAs.

Protection status sourced from Protected Planet / WDPA and refined with Marine Protection Atlas. Fishing pressure proxy is Global Fishing Watch AIS data. See the methodology for what these sources can and can’t prove.

Dive sites here

2 curated

Gear

What to bring

Basic kit

Site-specific add-ons

Some dive sites here call for extra gear. Check the individual site page for full context.

  • Long freediving finsThe dolphins set the pace. A few extra seconds of speed on the kick is the difference between a full pass and watching them disappear. · Chichijima Dolphin Swim
  • Snorkel and mask (no scuba)By prefecture rule and pod behaviour, encounters are snorkel/freedive only — bubbles drive the dolphins off. · Chichijima Dolphin Swim

What divers say

The 24-hour boat ride is part of the trip. By the time you arrive, you've earned the diving.
Ogasawara regular