Heian Maru
Chuuk Lagoon · Federated States of Micronesia
Truk Lagoon's largest wreck: a 163 m NYK ocean liner converted into a submarine tender, sunk during Operation Hailstone in February 1944. She lies on her port side with the uppermost hull around 12 m and the seabed at 34 m, her name still spelled out in huge raised letters across the bow. Forward holds are stacked with torpedoes and artillery shells; 15 m submarine periscopes rest in the superstructure beside gas masks and oxygen bottles. Soft coral and clouds of glassfish now cloak the vast steel flank divers drift across.
Conditions
Depth
12 to 34 m
Advanced depths
Current
Usually gentle
Can pick up on the edge
Visibility
15 to 25 m
Clearest in the calm season
Water
28 to 30°C
Tropical wetsuit
Month by month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Water (°C) | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 |
| Vis (m) | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 15 |
| Current | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle |
Your chances of seeing each animal
Glassfish
Last confirmed Apr 15, 2026 · 130 records
Almost always
Nearly every dive
Batfish
Last confirmed Feb 10, 2025 · 1 records
Likely
About 6 in 10 dives
Pacific Golden-Plover
Last confirmed Jun 28, 2026 · 16 records
Likely
About 6 in 10 dives
Micronesian Myzomela
Last confirmed Jun 28, 2026 · 15 records
Likely
About 6 in 10 dives
Lionfish
Expected
Known here, not yet in recent logs
Whitetip reef shark
Expected
Known here, not yet in recent logs
Peacock Damsel
Expected
Known here, not yet in recent logs
Bluefin Trevally
Expected
Known here, not yet in recent logs
Gear