Iro Maru

The Iro was a fleet oiler of the 1920s generation, a 143-meter tanker built in 1922 to keep warships fueled at sea. By early 1944 she was running supplies through an emptying empire. On 22 March the submarine USS Tunny put a torpedo into her bow; she limped into Palau's anchorage for repairs, and was still there on 30 March when Operation Desecrate One — the Palau counterpart to Truk's Hailstone raid — swept in. Carrier aircraft left her burning, and she went down upright in the sheltered water southwest of Koror. She has aged into one of Palau's signature wreck dives. Her kingposts rise like coral chimneys toward the light, a bow gun still sits on its bandstand platform above the torpedo-crumpled plating, and the aft superstructure opens into shadowy, manageable spaces. Between world-famous reef days, she is where Palau divers go to remember that the war passed this way too.

How she sank: Torpedoed by USS Tunny in March 1944, then sunk at anchor by carrier aircraft during Operation Desecrate One, 30–31 March 1944.

Condition: Upright and whole, with lagoon sediment softening her lines; the bow damage from the torpedo is still legible.

Penetration: Limited. The aft deckhouse and engine-room skylights admit trained wreck divers; deep machinery spaces are dark, oily, and best left alone. Entering any overhead environment requires specific training — a wreck certification at minimum, technical wreck training for full penetration.

Recommended certification: Advanced Open Water with deep experience

Current: Mild · Visibility: 10–20 m

Marine life: Soft corals and oysters crust the kingposts, batfish and barracuda circle the masts, and lionfish hold the gun platform.

Hazards: Lagoon visibility can drop with wind and tide; silt inside; residual oil films in overhead spaces.

Palau's wrecks are protected historic sites; permits through licensed operators apply.

Palau law forbids removing anything from its historic wrecks.