The Amatsu Maru is a must-visit wreck dive site in Palau for advanced divers seeking adventure and exploration. This 10,567-ton oil tanker, nicknamed the Black Coral Wreck, was sunk during the air raid Operation DESECRATE ONE on March 30-31, 1944. Since then, it has rested upright at a depth of 130 feet (40 meters), making it the deepest Japanese wreck in Palau.

The Amatsu Maru is the largest shipwreck in Micronesia, and its size and history make it a fascinating and exciting dive site. Located in West Malakal Anchorage, just a 5-minute boat ride from most dive shops in Koror, this wreck has become a popular destination for divers from all over the world.

Visibility at the Amatsu Maru varies from 80 feet (24 meters) at the bow to 20 feet (6 meters) at the stern. The wreck is covered in colorful soft corals and numerous bushes of black coral, making it a stunning sight for underwater photographers. There are no currents at this site, making it an excellent dive for intermediate to advanced divers with deep and wreck diving experience.

The Amatsu Maru dive site is also unique in that it is one of the few WWII Japanese wrecks in Palau that has not been salvaged extensively. The bow of the ship is raised above the main deck, and ladders on both sides connect it to the deck. The anchor winch and anchors were removed during the unsuccessful salvage operation in the early 1950s. However, part of the anchor chain can still be found scattered on the foredeck.

From the bow, moving aft toward the bridge, pipes, hoses, and large valves used for loading and unloading oils and fuels are visible. The bridge is constructed of three decks, the uppermost of which is the navigational deck. Some instruments can still be found on this deck. The bridge can be entered from above between the support beams. The wooden walls and floor structures were destroyed by fire or have deteriorated over time.

infographic of the Amaze Maru Wreck in Palau

The main fuel storage area behind the bridge features a large piping system that is now covered with extensive marine growth. Square holes were cut through the deck during the salvage attempt. The Amatsu Maru was hit directly by several 1000 lbs. bombs, and US Navy archive aerial photos were taken during the attack clearly show heavy smoke rising from the engine compartment. Diving through this section of the ship reveals huge piles of twisted metal, partly due to salvagers but mainly from a direct bomb hit.

At the stern of the ship, the twisted remains of a circular gun platform can be seen, although the gun is missing. If the huge 4-bladed prop is of interest, it is recommended to begin the dive at the stern before visiting the rest of the ship. To fully explore this large and magnificent WWII wreck, multiple dives may be necessary.

The Amatsu Maru has a length of 502 feet (153 meters) and a beam of 65.6 feet (20 meters). The reef formation surrounding the wreck is a 130-foot (40-meter) silt bottom with no coral formations. Marine life at this site includes various lagoon fishes.

For those interested in the history of the Amatsu Maru, it is important to note that many sunk and beached ships were salvaged in Palau after the war. The salvagers loaded the scrapped metal on some of the re-floated ships to tow them back to Japan. However, on the return trip, the entire salvage fleet was hit by a typhoon in the South China Sea and sunk. Not one ounce of scrapped metal ever made it back to Japan, as the ocean reclaimed what belonged to it.

Overall, the AmatsuMaru is a fascinating and rewarding wreck dive site in Palau. The site offers divers a unique glimpse into the past, with its well-preserved features and stunning coral growth. The depth of the wreck and its relatively intact condition make it a thrilling dive for advanced divers, but its easy accessibility and lack of currents make it a great choice for intermediate divers looking to take their skills to the next level.

One of the most striking features of the Amatsu Maru dive site is the abundance of black coral growth that adorns the ship's guardrails and superstructure. The coral adds a pop of color to the otherwise dark and imposing wreck, making it a stunning sight for underwater photographers. Divers can expect to see a variety of colorful soft corals and sponges as they explore the site.

While the Amatsu Maru may not have as many intact artifacts as some other WWII wreck sites in Palau, it still offers plenty of interesting features to explore. From the bow of the ship, divers can make their way toward the bridge, taking in the various pipes, hoses, and valves used for loading and unloading the oils and fuels. The bridge itself is a multi-level structure, with the uppermost deck containing navigational equipment and instruments that have been preserved over the years.

Divers can also explore the main fuel storage area behind the bridge, which features a large piping system now covered in marine growth. The square holes cut through the deck during the salvage attempt offer an eerie reminder of the ship's troubled past, while the piles of twisted metal reveal the true power of the bombs that struck the Amatsu Maru during the war.

At the stern of the ship, divers can observe the twisted remains of a circular gun platform, which once housed a gun that is now missing. The 4-bladed prop at the stern of the ship is another impressive feature that divers won't want to miss.

One thing to keep in mind when diving the Amatsu Maru is that there is no marker buoy at the site. Divers should rely on the expertise of their dive guide, who will locate the wreck and tie the boat to an anchor line. The dive typically begins at the bow section of the ship, and it is recommended that divers begin their exploration at the stern if they are interested in seeing the prop.

Overall, the Amatsu Maru is an impressive and memorable dive site in Palau that offers a unique glimpse into the region's WWII history. With its depth, intact features, and stunning coral growth, it is a must-visit site for advanced and intermediate divers alike.