Federated States of Micronesia · Chuuk

Chuuk Lagoon

Main wreck-diving season with more settled weather.

Chuuk Lagoon (Truk) holds the largest concentration of WWII shipwrecks on Earth — 60+ Japanese vessels and aircraft sunk in Operation Hailstone in 1944, now coral-encrusted and intact. It's the world's premier recreational wreck destination.

Good season

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

Year-round; December–April is driest. Water temp is a steady 28–29°C.

Trip duration

7–10 night liveaboard, or land-based at Blue Lagoon Resort.

Dive style

Wreck penetration, often deep (30–40m). Nitrox standard; many divers add rebreathers and technical training.

Dive level

Advanced + wreck specialty for penetration; tech training recommended for deep wrecks.

Reef health

What you’ll actually find
Mixed

Some loss since the 2010s, but the reef still has plenty to dive. Pick depth and shoulder-season carefully.

Coral reef health

How is this calculated?
A decade ago
Survey 2014
37%
Today
Survey 2024
35%

On current trend, no live coral by ~2199. Losing about 0.2% cover per year — roughly 175 years of reef left to see if nothing changes.

Heat stress right now

Watch

Mild warmth. Worth watching — no bleaching yet.

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

What to expect on a dive

WWII Japanese fleet with extensive coral growth on the wrecks. Lagoon conditions remain stable.

Sources, methodology, and the raw numbers

Raw observed numbers

  • Coral cover: 35% (survey Sep 2024, Chuuk Lagoon coral-on-wreck benthic survey)
  • Bleached: 8%
  • Recent mortality: 2%
  • Chuuk lagoon — observed condition reflects the stable regional pattern.

Raw thermal numbers

  • NOAA CRW alert level: Watch
  • Degree Heating Weeks: 0 °C-wk
  • SST anomaly: +0.7 °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

Moderate fishing pressure

Dominant pressures

  • industrial fishing on EEZ edges
  • warming

1 Green Fins-verified operator known at this location.

What you can do

Chuuk wrecks are legally protected as cultural heritage under Micronesian law. Yap, Chuuk, and FSM mix traditional tenure with national park designations. Chuuk wrecks are legally protected as cultural heritage.

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

5 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.

  • Dive lightCargo holds and engine room penetration — primary plus backup. · Fujikawa Maru
  • ComputerMulti-level deep wreck — Nitrox recommended. · Fujikawa Maru
  • ComputerTrimix dives common to maximize bottom time. · Shinkoku Maru

What divers say

Swimming through the engine room of the Fujikawa Maru is like time-travel with a regulator in your mouth.
Wreck diver