Olympia Maru

Olympia Maru: A Journey into Coron's Underwater History

Prepare for an unforgettable dive into history at the Olympia Maru, one of Coron Bay's most iconic World War II wreck dive sites. This impressive Japanese army cargo ship, measuring approximately 137 meters long and displacing 5,617 gross tons, rests upright on the seabed, offering an incredible exploration for divers of varying experience levels.

The Wreck: An Upright Time Capsule

The Olympia Maru met its fate on September 24, 1944, during a fierce US air attack. Reports indicate that the fourth US aircraft scored a direct hit amidships, likely striking a fuel tank and severely damaging the engine, leading to its sinking. Today, the wreck sits largely intact and upright, with its main deck typically found between 18 meters and 24 meters deep, and the bottom reaching a maximum depth of around 32 meters. Divers will find the port superstructure heavily encrusted with vibrant marine growth, including massive lettuce corals and dark black coral formations. While often confused with the nearby Morazan Maru, the Olympia Maru is a distinct and captivating dive site.

Diving the Olympia Maru

We classify the Olympia Maru as an intermediate dive site, with moderate currents sometimes present, which can enhance the marine life sightings. Water temperatures in Coron generally range from 26°C to 31°C, making for comfortable diving conditions year-round. For those with an Open Water certification, the deck offers an excellent opportunity for exterior exploration. However, to truly appreciate the wreck's interior, an Advanced Open Water certification is required for penetration dives.

The vast forward and aft cargo holds of the Olympia Maru remain wide open and often sunlit, making this an ideal, low-stress site for introductory wreck penetration where ambient light reaches deep inside. More experienced divers can explore challenging penetration opportunities, including navigating through the propeller shaft from the exterior into the engine room.

Marine Life and Hazards

The Olympia Maru is teeming with diverse marine life. Divers can expect to encounter large schools of fish, including batfish, snappers, and barracuda, particularly around the mast, bow, and stern. Keep an eye out for the vibrant Sea Goldie (Pseudanthias squamipinnis), Oriental Sweetlips (Plectorhinchus vittatus), and the charming Clownfish (Amphiprion ocellaris) nestled among the corals. You may also spot Masked Rabbitfish (Siganus puellus), various nudibranchs, and eels.

However, divers should remain vigilant for potential hazards. Scorpionfish, such as the Devil Scorpionfish (Scorpaenopsis diabolus), are common and well-camouflaged, so we advise careful buoyancy control and awareness of your surroundings. Entanglement risks from fishing lines or debris, sharp metal edges within the wreck, and the overhead environment during penetration dives are also considerations. We always recommend diving with a qualified instructor or guide familiar with the site.