Dive Site: Gosei Maru

About Gosei Maru

The Gosei Maru is a compelling wreck dive in Truk Lagoon, Micronesia, offering a glimpse into World War II history beneath the waves. This coastal freighter, approximately 155 meters (509 ft) long, lies on its port side, providing a unique topography for exploration. Unlike some of the larger, more imposing wrecks in the lagoon, the Gosei Maru presents a more compact and accessible profile, making it a favorite for divers seeking detailed wreck exploration without extreme depths. Originally sunk during Operation Hailstone in February 1944, the Gosei Maru has since transformed into a vibrant artificial reef. Its structure is now richly adorned with soft corals and sponges, attracting a diverse array of reef fish and macro life. Divers can expect to discover fascinating cargo remains within its holds, adding a tangible connection to its past. The dive site is celebrated for its quieter, more serene atmosphere, allowing for focused observation of both the wreck's historical artifacts and its thriving ecosystem. The general conditions in Truk Lagoon, including minimal currents and warm water temperatures, contribute to a relaxed diving experience on the Gosei Maru. Exploration typically involves descending along the wreck's length, investigating the holds and superstructure, and observing the marine life that has made this sunken vessel its home. The Gosei Maru is particularly noted for its photographic opportunities, capturing both the grandeur of the wreck and the intricate details of its biological inhabitants.

Dive site facts: Gosei Maru

Depth

3–31 m

Current

Mild to none

Visibility

10–25 m

Water temperature

27–30°C

Entry

Boat

Level

Open Water Diver

Dive type

Wreck, historical, macro

Night dive

Possible

Region / port

Truk Lagoon, Micronesia

Coordinates

7.348, 151.855

Conditions & Currents

Diving conditions around the Gosei Maru in Truk Lagoon are typically very calm, with little to no current experienced on most dives. This makes for a relaxing and accessible dive, suitable for divers who prefer minimal water movement. Visibility in the lagoon generally ranges from 10 to 25 meters, though it can vary. Water temperatures are consistently warm, between 27 to 30°C (81-86°F). While surface conditions can occasionally be choppy due to higher winds between April and November, the protected nature of the lagoon means underwater stability is maintained, ensuring a comfortable experience for exploring the wreck.

Marine life & sighting chances

Soft corals

common

Sponges

common

Reef fish

common

Lionfish

occasional

Nudibranchs

occasional

Moray eels

occasional

Small crustaceans

occasional

Anemones

common

Grey reef sharks

occasional

Dive profile & how the dive runs

The Gosei Maru offers a flexible dive profile, typically starting with a descent to the wreck, which lies on its port side, with the shallowest parts starting around 3 meters. Divers can explore the deck and superstructure, which are extensively covered in marine growth, often at depths ranging from 10 to 20 meters. The cargo holds, where various historical artifacts may be found, extend deeper, reaching up to the maximum depth of 31 meters. A common route involves tracing the length of the vessel, moving between exterior observation of marine life and careful penetration into accessible holds, ensuring adequate bottom time for exploration. The dive concludes with a gradual ascent, allowing for a safety stop, often performed along the wreck's shallower sections or with a deployed safety sausage.

Underwater photography

The Gosei Maru is an excellent subject for both wide-angle and macro photography. For wide-angle shots, a fisheye or wide-angle rectilinear lens is ideal to capture the freighter's overall structure and the extensive soft coral growth, especially when ambient light penetrates shallower areas. Consider shooting from slightly below the wreck to emphasize its scale against the open water. For macro subjects, such as nudibranchs, small crustaceans, and intricate coral polyps, a macro lens with a focus light will reveal incredible detail within the wreck's crevices and cargo. Pay close attention to buoyancy to avoid disturbing silt inside the holds, which can significantly reduce visibility and photographic opportunities. Using strobes can enhance colors and bring out details in darker sections, but be mindful of backscatter in areas with suspended particles.

Combine with nearby dive sites

• Fujikawa Maru

  A large freighter known for its cargo of Zero fighter planes and gas masks.

• Shinkoku Maru

  Features beautiful soft corals and an interesting engine room.

• Nippo Maru

  A medium-sized freighter with a variety of artifacts.

• Rio de Janeiro Maru

  A combined passenger-cargo liner with holds full of shells and beer bottles.

• Heian Maru

  One of the largest wrecks in the lagoon, offering extensive exploration.

• Yamagiri Maru

  A cargo vessel with unique historical cargo.

Getting there & logistics

Diving the Gosei Maru typically involves liveaboard trips operating from Truk Lagoon (also known as Chuuk), Micronesia. The primary international airport is Chuuk International Airport (TKK). Liveaboards usually offer 7-day or 10-day itineraries, providing access to multiple wrecks within the lagoon. Park fees and permits for diving in Truk Lagoon are often included in liveaboard packages. Itineraries are meticulously planned to allow for multiple dives on different wrecks each day, sometimes with repeat dives on a single site to ensure thorough exploration. Divers should confirm any visa requirements for Micronesia prior to travel.

Safety & environment

Safety for diving the Gosei Maru, like all Truk Lagoon wrecks, requires adherence to standard diving practices and specific wreck diving protocols. The nearest recompression chamber is located in Weno, Truk Lagoon, but evacuation for serious medical emergencies can be complex and time-consuming, potentially involving air ambulance to Guam or further. Divers must carry comprehensive dive insurance that covers emergency medical treatment and evacuation. Site-specific hazards on the Gosei Maru include potential entanglement in fishing lines or loose debris, sharp metal edges, and the risk of disturbing silt, especially during penetration. Always dive within your certification limits, follow your dive guide's instructions, and never remove artifacts or disturb human remains.

Who it suits — and who it doesn't

FAQ

Gosei Maru FAQ

Liveaboards diving Gosei Maru

These liveaboards may visit Gosei Maru on selected itineraries — the exact dive sites depend on departure, weather and conditions.

Palau Siren

Micronesia

16 guests

$501/day

Solitude Gaia

Micronesia

18 guests40 m

$310/day

Palau Aggressor II

Micronesia

18 guests32 m

$360/day

Black Pearl

Micronesia

24 guests

$390/day

Ocean Hunter 3

Micronesia

16 guests29 m

$350/day

Pacific Master

Solomon Islands

20 guests30 m

$268/day