Iro Maru Wreck Liveaboard Diving

The Iro Maru rests south of Koror in Palau, one of several WWII wrecks scattered through Palau's waters from the March 1944 US air raids known as Operation Desecrate One. It's a boat dive reached from Koror-based operators rather than a shore or beach dive.

The wreck's upper deck sits at about 82 ft (25 m), with the seabed around 131 ft (40 m), making it a genuinely deep wreck dive reserved for advanced or technical divers. Its more vertical profile compared to flatter lagoon wrecks adds to the depth management challenge.

It was a Japanese Navy oiler — a fuel-supply ship roughly 469 ft (143 m) long — sunk during WWII while supporting Japan's Pacific Fleet operations. Oilers like the Iro Maru were high-value targets since fuel shortages crippled Japanese naval mobility later in the war.

Divers can spot deck guns, kingposts, and clear torpedo damage in the bow, all coated in decades of coral growth that gives the structure a heavily encrusted, almost reef-like appearance. Its upright, largely intact hull makes for straightforward wreck orientation despite the depth.

No — depths of 82 to 131 ft (25 to 40 m) put this wreck firmly in advanced or technical diving territory, with an emphasis on depth management and wreck procedures rather than casual sightseeing. Most operators require advanced certification and solid experience before booking this dive.

Yes, for suitably trained divers — the wreck is considered suitable for penetration by advanced divers, though its depth means bottom time is limited and careful planning is essential. Guides typically restrict interior access to those with wreck diving certification.

Marine life is generally described as average for the area, with small reef fish and encrusting coral rather than the big pelagic action found at sites like Blue Corner. The wreck itself, rather than the marine life around it, is the main draw here.

It's accessible only by boat through a local Koror-based dive operator, given its offshore location, depth, and technical demands. There's no way to reach or view the wreck without a guided dive trip.

December through March generally brings calmer seas and clearer conditions in Palau, which matters even more on a deep dive like this one, where good visibility helps with orientation and safety. Dive shops typically only run trips there when conditions cooperate.

It was sunk during World War II air strikes on Japanese shipping around Palau, part of the broader US campaign (including the March 1944 Operation Desecrate One raids) that targeted the fuel and supply vessels supporting Japan's Pacific Fleet. Torpedo damage visible in the bow today is a direct remnant of that attack.

The wreck measures roughly 469 ft (143 m) long, a substantial oiler that gives technical divers plenty of structure to explore across multiple dives. Its size and depth mean most divers need more than one trip to see it properly.

Advanced Open Water at minimum, with many operators preferring deep-diving or wreck specialty certification given depths beyond 100 ft (30 m). Divers should also be comfortable with the added risks of depth-related narcosis and limited bottom time.

It can be, though it's less commonly featured than headline sites like Blue Corner or German Channel, since its depth and technical demands make it a better fit for wreck-focused itineraries or advanced groups requesting it specifically. Worth confirming with your operator if it's a must-dive for you.

A dive computer suited to deeper profiles, a reliable primary and backup light, and careful air-supply planning (or nitrox/technical gas, where certified) are all worth having given the depth. A wide-angle camera can capture the guns and torpedo damage, though low light at depth calls for a strobe or good external lighting.

It's deeper and generally less decorated with artifacts than famous Truk Lagoon wrecks like the Fujikawa Maru, making it more of a specialist's dive than a headline attraction. Divers chasing Palau's wall and shark diving sometimes add it as a change of pace, but most come to Palau primarily for Blue Corner and German Channel rather than its wrecks.