Best dive wrecks in Chuuk Best dive wrecks in Chuuk

Chuuk, formerly known as Truk, is one of four island states that make up the Federated States of Micronesia (FSM), a country in the North Pacific that is part of the Mariana Islands. The FSM is also one of the least visited countries in the world.

Those who have heard of Chuuk before will know it because of the role it played in World War II and, in particular, because of the wrecks that fill Chuuk lagoon as a result of bloody Operation Hailstone. Rad on to found out the history as well as the best dive wrecks in Chuuk.

What was Operation Hailstone?

Dive bomber over Chuuk in 1944

Dive bomber over Chuuk in 1944 (Source: wikipedia)

Chuuk’s recent history is bloody, tragic and infamous. As the center stage of Operation Hailstone, the 1944 US attack on the Japanese combined fleet that was stationed in Chuuk Lagoon, the waters of this peaceful nation are filled with the remnants of this deadly attack. Several dozen ships, submarines, carriers, tankers, flying boats, bombers and aircrafts still lay at the bottom of the ocean, mostly intact. Although the majority of the human remains were removed in the early 2000s for burial by the Japanese government, some fragments of bones and skulls can still be found while diving at higher depths.

Chuuk was the major center of the Japanese Navy fleet operations in the Pacific during WWII and had been under its influence since WWI. It was also the largest navy point outside of mainland Japan. As a result, the rest of the international powers knew little about the area and it was believed by the Japanese to be a safe anchorage for the many aircrafts and ships of the Combined Fleet. Until a pair of US reconnaissance aircrafts taking off from the recently conquered Marshall Islands gathered evidence in 1944, the range and extent of the Japanese navy presence in the area was uncertain.


Given the size of the Japanese fleet in Chuuk that the reconnaissance planes reported on, the US and Allied Forces decided that, to ensure their supremacy in the Pacific, the Lagoon had to be attacked and the Fleet destroyed. Admiral R. Spruance decided to attack it with several battleships and other support ships able to carry 500 aircrafts with the objective of destroying the runways and all the ships in the area. He hoped that some of the flagship battleships of the Combined Fleet were also stationed there.

At its peak, Japan had 30,000 troops in Chuuk and the two largest battleships ever constructed were based there. One week before Operation Hailstone, when it realised that the reconnaissance planes had discovered their mighty fleet, Japan relocated the battleships and a large part of the Combined Fleet to Palau. The Allied Forces used to refer to Chuuk as the Gibraltar of the Pacific or Japan’s Pearl Harbour.

On the break of February 17th 1944, the American carriers launched several F6F Hellcat planes into the airspace to ensure clear skies only to find them completely empty. The attack took the Japanese fleet by surprise and there was little they could do to defend at such short notice. Over the two-day operation, a total of 50 ships were sunk. As many as 250 aircrafts were destroyed, many in various stages of assembly, as they had arrived aboard cargo ships in pieces. The US also lost 25 aircrafts and had three battleships damaged with dozens of crew members losing their lives.

Operation Hailstone was the largest aerial coordinated strike in history with over 500 planes participating in it and it was considered a major success in that it almost annihilated the Japanese presence in Chuuk deeming the base inoperative by the Japanese Army and destroying all the 4 airstrips, the Command Center, the shipyard and the submarine base. Aside from the many Japanese soldiers who lost their lives during the attack, thousands were stranded on the islands without any supply lines to their country after Operation Hailstone and subsequent attacks and died of starvation. Eventually, the Japanese Command surrendered Chuuk in September 1944 and the US took control in November 1944 and began reconstruction. Operation Hailstone was deemed a turning point in the Pacific stage of WWII as it diminished Japan’s ability to stay in battle.

Jacques Cousteau Lagoon of Lost Ships


Until the 60s, Chuuk Lagoon was largely undiscovered and undocumented. That is, until Jacques Cousteau arrived with a crew to film the main wrecks for the documentary The Lagoon of the Lost Ships. At that time, most of the human remains from the tragedy still laid intact, engulfed by the corals and calm waters of the lagoon, and Cousteau did not know most of the names of the ships he was surveying and filming. Their names were revealed later thanks to books like WWII Wrecks of the Truk Lagoon. The documentary made Chuuk famous and put it on the map for avid WWII and diving fanatics.

The best wreck dives in Chuuk

The Chuuk Government has made it illegal to remove artifacts from the wrecks and has declared it a National Treasure, so preservation is strong. Although wrecks are usually home to large fish in most parts of the world, that is not the case in Chuuk where there is rich marine life but it is more in the form of soft corals, sea sponges, anemone and sea fans filled with corals and fish but no large marine life. It is believed that the large amounts of oil dropped into the lagoon during Operation Hailstone polluted the waters killing everything in it.

There are between 50 and 70 wrecks in the lagoon. As some of them are really deep, Advanced or Technical diving certifications are required. But even with an Open Water PADI certification you can go out diving every day for a week and never run out of options. In fact, some of the wrecks are close to the surface and are even visible to snorkelers. The dive masters and guides are relaxed about your certification and ability to dive. When I signed up at Blue Lagoon Dive Center I saw everyone above me having hundreds and even thousands of dives under their belt whereas I was under 100. I was not asked to provide my Open Water ID or registration number and a pen written registration on a book was enough.

Dive boats were bare and every diver I met, except for me, had carried his or her equipment entirely (sometimes even the tanks) from their home all the way to Chuuk. Equipment rental is possible, but if you stay for a few days, it will be costly and it will be more economical to buy and bring your own. I spent USD75 a day on gear rental. As the dive guides are used to professional divers on their boats, there will be little provided other than a couple of dry boxes. If you need liquid to clean your mask, bring your own or use good old spit.

Once in the water, you will buddy up, but the guide let everyone pretty much fend for themselves, just keeping an eye on everyone and pointing at the holes we could go in. As I was the least experienced diver on every trip and I was diving alone, I buddied up with the guide and this proved to be a great way to identify the key parts in every wreck. Unless you know what you are looking for and where, staying close to the dive guide will ensure you can find the guns, ammunition, bones and all the key parts. Underwater and with the coral growth, it is difficult to recognise anything. A torch will be most useful, especially inside the wrecks where it can be very dark. Gloves are a must so you can squeeze through doors and torpedo holes without scratching your hands.

PADI’s Encyclopedia of Recreational Diving lists Chuuk Lagoon as one of 4 wreck diving “Meccas” in the world. Its many wrecks have been featured in notorious publications as some of the most important and interesting in the world. At least three of them are included in Sport Diver 50 Best Wreck Dives. Although there are several dozen ship wrecks, here are a few of the most iconic ones.

1. Fujikawa Maru wreck

The iconic Fujikawa Maru workshop compressor, Truk Lagoon. #truklagoon #fujikawamaru #wreckdiving #r2d2 #robkohl

A photo posted by Seal Sports (@sealsports) on

Originally built as a passenger and cargo ship between the Orient and America it was transformed into an armed aircraft transport ferry by the Japanese Imperial Army. Bringing it down required several hits by aircrafts, dive bombers and torpedoes.

The Fujikawa Maru is often referred to as the “Showcase Wreck” and is easily dived as it lays between 9 and 33m. The bow gun is easily spotted. Interestingly, it was produced by a British manufacturer in 1899 during the Russo-Japanese War. There are fighter plane fuselages and other parts of planes in the holds and the superstructure is easily accessible. The telegraph annunciator is covered with beautiful corals. You can go down to the engine room through eerie staircases to see how a ship this size was powered. There is no light at such depths so the sense of mightiness is extreme. The Fujikawa is also famous for the air compressor warmly named R2D2 which features in many a diver’s photograph. A lot of small artifacts provide an insight into a Japanese warship. Hold No.2 contains parts and fuselage of Zero planes which can be seen up close.

In 1974 a Japanese delegation placed a glass shrine on top of the bridge with the names of the crew members inside.


2. Rio de Janeiro Maru Wreck

Originally a luxury cruise ship ending its trip in Rio De Janeiro, this ship sank after being hit by several 1,000 lb. bombs during air attacks. Rio de Janeiro Maru was discovered in 1978-1980 and it is at various levels of depth.

Divers who make their way down there will see the 6″ deck gun above the forecastle with its barrel pointing down and lots of ammunition underneath. Another 6″ gun is aft. Both of them are a remnant of the Russo-Japanese war. Penetration into the engine room is possible.

The ship’s name is clearly visible on the side of the bow. Inside the No.1 hold there are artillery shells and debris. Large guns are in the second hold while winches and cargo equipment are above. The portholes on the bridge are “D” shaped and their glass is still intact.


3. Heian Maru Wreck

Heian Maru

Heian Maru

Built in the 30s as a merchant ship, it was fitted with the finest decorations. It was then converted into a submarine tender. Heian Maru was hit by several hell divers and then by a torpedo strike which sank it to its side.

This is one of the Must-Dive wrecks in Chuuk Lagoon as there are many relics and the interior is easy to penetrate. Inside, you can see a torpedo long lance, an innovation of the time in its ability to project the torpedoes much farther. The Heian was also carrying replacement periscopes. As most of the wrecks in Chuuk have been spared of major robbery, the ship propellers are still intact.


4. Aikoku Maru Wreck

Originally designed as a combined luxury passenger liner and cargo vessel for South America and around the world, Aikoku Maru was then recommissioned as a war ship on its first day as a radar merchant.

It sank during Operation Hailstone when a torpedo hit the No.1 cargo hold and detonated stored ordnance. Aikoku sank in only two minutes with the 945 crew and 400 troops, many of whom died from the shock wave. The soldiers were on their way to the Marshall Islands. Although the wreck was first discovered by Cousteau, its name was unknown then. In 1980, the remains of 400 people were recovered, cremated in a ceremony and their ashes sent back to Japan.

The effect of the explosion can be seen in today’s wreck where the ship abruptly ends at one side and the rest is just rubble on the seabed.


5. Nippo Maru Wreck



The Nippo Maru was originally a water and ammunition delivery ship. One of the most dived wrecks thanks to its relatively shallow location, the Nippo Maru contains a tank, coastal defense guns, mines, munitions, anti-tank guns and water tanks. Inside the forecastle are many personal effects of the crew in the silt. The forward hold contains mines, detonators, artillery shells and gas masks, one of the shocking diver images of this wreck.

Hold No.1 contains large bronze range finders and a tank that was probably transported in the event of a US ground invasion of Chuuk. Three howitzers are on the deck near Hold No.4 which is filled with lots of beer bottles, radio equipment and a variety of items.

6. San Francisco Maru Wreck

San Francisco Maru

San Francisco Maru

San Francisco Maru was first built in 1919 and used in prewar trade operations. It was then used to transport cargo in WWII and finally ended in Chuuk lagoon one week before Operation Hailstone where it was hit by a bomb mid-ship and sank immediately.

The wreck was discovered by Cousteau but not dived then. Later on, in 1973, it was re-discovered and has been dived since. It is considered one of the most incredible wrecks of Chuuk and often referred to as “The Million Dollar Wreck” because of the value of its cargo. This is also one of the best wreck dives in the world. The valuable cargo was there probably to defend from an American amphibian attack that never occurred.

It is located pretty deep at 48m for the main deck, so you must be a technical diver. There is a 3” bow gun encrusted with corals. Hold No.1 contains spherical sea mines and their detonators and “horns” for detonation on contact in boxes nearby. In Hold No.2 there are several trucks, a favourite with divers, barrels of fuel and aerial bombs. The bridge area is intact and the crew quarters have all sorts of utensils and china.

Another great shot of this wreck is the three Type 95 Ha Go tanks on the deck, two of which are on top of each other as a result of the explosion which sank it. On the sea bed are a large truck, steam roller and another truck. The aft holds artillery shells, torpedoes and depth charges.

7. Shinkoku Maru Wreck

Bow gun on Shinkoku Maru, Chuuk

Bow gun on Shinkoku Maru, Chuuk

One of the “Must-dive sites” in Chuuk Lagoon is the Shinkoku Maru, a tanker measuring 152m and found at 12m, bottoming up at 36m that requires multiple dives to explore. The deck, where many of the interesting bits are found, is only 18m deep. Look out for the operating table and medicine bottles, some bones, toilets and a Japanese style tiled bath. The telegraph and the wheelhouse can be accessed through a stairwell.

Outside, the gun bow is visible and completely covered with beautiful soft and bright corals and there are tables with sets of plates and bottles in perfect state and even two urinals with the Japanese brand still visible. Some of the stunning neon anemones, with their respective clown fish, cover the outer areas of the ship. A particularly bright fuchsia anemone will catch your attention.

Shinkoku Maru’s masts are used to stick out of the water but were removed to avoid ship damage. The wreck was then forgotten and only re-discovered in 1971. Advanced divers can make it down to the engine room at higher depths.

8. Other noteworthy wrecks

The Hoki Maru is interesting for the vintage pick-up trucks and the thousands of beer bottles, a common feature of most ships in Chuuk.

The Fumitzuki Destroyer was found at repair anchorage with engines disabled and unable to move at the time of Operation Hailstone. It is an easy dive because of its very shallow position and intact cargo. The ship was a companion destroyer sent to protect merchant vessels and filled with depth charges used to destroy submarines below. Divers can see the living quarters and personal effects. This is also a place where marine life is abundant, including guitar sharks which can sometimes be spotted.

Fujisan Maru was an oil tanker. This is a deep ship wreck usually dived as a two tank. The depth also means clear waters and less corals and marine life.

The Yamagiri was being repaired when it was attacked. The beautiful sea fans growing on the wreck make for an amazing underwater coral forest. In Hold No.5, divers can see ammunition and torpedoes. The false sea bed created by the fallen wreck has amassed an incredible marine life.

The Hanakawa Maru is located after about a 2h boat ride from Weno, so it is rarely dived. This means the superstructure and the corals are in perfect condition as they are not often disturbed.

Sankisan Maru was loaded with ammunition so, when hit, it exploded into two pieces. Packed in the cargo holds are trucks, tanks, ammunition and the marine life and corals here are stunning.

Cousteau had probably the best closing remark to define Chuuk:

“Truk Lagoon presents a mysterious planet of life and death. On the one hand, nature absorbs the artifacts of war. And on the other, she has preserved them. Only centuries from now, will every trace of man’s follies vanish from the bottom of Truk Lagoon.”

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Best dive wrecks in Chuuk Best dive wrecks in Chuuk