Azumasan Maru

Best months: Jan–Dec

Protected Area

Komarindi

Why dive here

With 391+ marine species recorded in the area - including barracuda, blacktip reef sharks, grey reef sharks, humpback whales and orcas - Azumasan Maru offers some of Iron Bottom Sound's richest wreck diving. Water sits around 30°C.

Marine lifeBarracuda, Blacktip Reef Sharks, Grey Reef Sharks, Humpback Whales and Orcas · 391+ species recorded

Water30°C · warmest January, February, March

CharacterWreck dive

StandoutExceptional marine biodiversity

The Azumasan Maru is one of those wrecks we keep coming back to in Iron Bottom Sound. She’s not one of the colossal ones, but her character really shines. Sitting upright, the bow is the shallower end, peaking around 34m, which means you get a good chunk of bottom time if you're mindful of your deco. We always start at the bow, dropping down to that sandy patch to look back at the silhouette; it's a fantastic shot, especially if you catch some schooling fish in the foreground. Our favourite part, though, is the cargo. Head to the second hold, and you'll find a jumble of motorbikes and sidecars. It’s a real snapshot of wartime logistics, frozen in time. Around the wreck, the soft corals have really taken hold, painting the metal in purples and oranges. Look closely, and you’ll spot Hexagon Groupers peeking from crevices, and the flash of Black Butterflyfish against the hull. Visibility averages around 15m, which is decent enough to appreciate the scale and the details, but keep an eye on your depth here; it slopes quickly past the bow. This site really suits divers who appreciate historical context and enjoy a bit of wreck penetration without going too deep or complex.

Safety Notes

Wreck site - avoid penetration without wreck diving certification. Watch for sharp metal and entanglement hazards.

Today06:2818:2011h 52m daylightGolden hour 17:52

Azumasan Maru Wreck History

Year Sunk

1942

Vessel Type

cargo ship

Cause

grounding

Tonnage

7,623 GRT

The Azumasan Maru began her life in 1933 as a civilian freighter for Mitsui Bussan Kaisha. With the outbreak of war, she was requisitioned by the Imperial Japanese Navy and converted into a troop transport, a role that would seal her fate in the Solomon Islands. She participated in the initial invasion of Tulagi in May 1942, where she was damaged by aircraft from the USS Yorktown. Her final mission was as part of the 'Tokyo Express,' a convoy desperately trying to resupply Japanese forces on Guadalcanal.

On October 15, 1942, while unloading troops and supplies near Tassafaronga Point, the convoy came under relentless attack from US aircraft based at the nearby Henderson Field. Severely damaged by dive bombers, the Azumasan Maru's captain deliberately beached her to prevent sinking and salvage her precious cargo. She was hit again by B-17 bombers the next day, ensuring she would never sail again. Today, she is a spectacular technical dive, sitting upright on a steep slope that drops into the depths of the legendary Iron Bottom Sound. The bow rests around 40-50 meters, while the stern plummets to over 80 meters. The wreck is adorned with vibrant soft corals and is a world-class site for underwater photographers, offering a hauntingly beautiful window into a pivotal moment in WWII history.