Azumasan Maru - Iron Bottom Sound

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.

Location
Iron Bottom Sound, Solomon Islands, Central & South Pacific
Coordinates
-9.351400, 159.845600
Type
wreck

Wreck History - Azumasan Maru

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.

Marine Protected Area: Komarindi

Best Time to Dive in Iron Bottom Sound

The warmest water temperatures in Iron Bottom Sound occur in January, averaging 30.5°C. The coolest conditions are in December at 30.5°C.

Monthly Water Temperatures

  • January: 30.5°C (air: 26.9°C)
  • February: 30.5°C (air: 26.7°C)
  • March: 30.5°C (air: 26.7°C)
  • April: 30.5°C (air: 26.8°C)
  • May: 30.5°C (air: 26.9°C)
  • June: 30.5°C (air: 26.5°C)
  • July: 30.5°C (air: 26.5°C)
  • August: 30.5°C (air: 26.3°C)
  • September: 30.5°C (air: 26.5°C)
  • October: 30.5°C (air: 26.7°C)
  • November: 30.5°C (air: 26.7°C)
  • December: 30.5°C (air: 26.9°C)

Nearby Dive Sites in Iron Bottom Sound

Nearest Dive Centres to Azumasan Maru

Marine Life in Iron Bottom Sound

Home to 415 recorded species including 320 reef fish, 29 hard corals, 18 sea snails & nudibranchs, 16 sea cucumbers, 7 seagrass & algae, 5 clams & mussels.

Notable Species

Recommended Packing List for Azumasan Maru

Based on average water temperature of 30.5°C.

  • Shorty or Rashguard - warm 30°C water needs minimal exposure protection
  • Mask - essential for every dive
  • Fins
  • BCD - buoyancy compensator
  • Regulator - your most safety-critical piece of gear
  • Dive Computer - tracks depth, time, and NDL
  • Surface Marker Buoy (SMB) - essential for boat pickups
  • Dive Torch - useful for crevices and colour at depth
  • Underwater Camera - capture your diving memories

Frequently Asked Questions

What is the maximum depth of the Azumasan Maru wreck for divers?
The maximum depth for divers on the Azumasan Maru wreck is 34m. While parts of the wreck extend deeper, such as the bow at 39-50m and the stern at 80m plus, this 34m depth is the recommended limit for recreational diving. It provides ample opportunity to explore the wreck's features safely.
What kind of artifacts or marine life can divers expect to see on the Azumasan Maru?
Divers exploring the Azumasan Maru can expect to encounter a vibrant display of marine life, including lots of color and soft corals. Additionally, the wreck holds fascinating artifacts such as motorbikes and sidecars in its second hold, offering unique photo opportunities. You'll find excellent photo spots, especially when looking back at the wreck from the sand near the bow.
How challenging is the Azumasan Maru dive, and is it suitable for all experience levels?
The Azumasan Maru is rated as an intermediate difficulty dive. This means it is not suitable for all experience levels, and divers should possess appropriate training and experience for wreck diving and deeper profiles. It offers a rewarding experience for those with the necessary skills and certifications.
What is the best time of year to dive the Azumasan Maru for optimal conditions?
The provided data does not specify the best time of year to dive the Azumasan Maru for optimal conditions. For general information on seasonal diving in the Solomon Islands, you might consult our When to Dive guide. We recommend checking local dive operators for current conditions.
What diving certifications are required to dive the Azumasan Maru?
While specific certifications are not explicitly listed, given the Azumasan Maru's intermediate difficulty and maximum depth of 34m, divers would typically need advanced open water certification or equivalent. Specialized wreck diving training would also be highly beneficial to safely explore its features, such as the motorbikes in the second hold. Always dive within your training and experience limits.
What are the typical currents and underwater conditions like at the Azumasan Maru dive site?
At the Azumasan Maru dive site, divers can expect an average visibility of 15m, offering good views of the wreck and its vibrant marine life. The provided data does not specify typical current conditions for this site in Iron Bottom Sound. It's always wise to consult with local dive operators for up-to-date information on currents.