Coron Wreck Diving: WWII Japanese Fleet in Palawan

Coron wreck diving is a fleet, not a single celebrity hull. On 24 September 1944, aircraft from US Task Force 38 found Japanese supply ships sheltering in Coron Bay, Palawan, and sank several of them in one raid. What you dive today is that morning: tankers, cargo ships, a seaplane tender, gunboats — coral-covered steel in a sheltered Philippine bay.

People compare Coron with Truk. The comparison is fair on theme (Pacific war, warm water, wreck-dense days) and unfair on logistics. Coron is a town-and-banca operation, cheaper for many travellers, and more mixed in depth. You can be Open Water on Okikawa Maru’s deck in the morning and still have no business on Irako’s sand in the afternoon.

This guide is a destination map: the story of the raid, the wrecks by depth and license, access from Coron town, and the silt-and-penetration rules that get skipped in brochure photos. It belongs on any best wreck diving in the world list that is honest about certification. For the skill itself, use the wreck diving hub.

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The Story of the Wrecks

By late 1944 the Japanese navy was losing the Philippine campaign. Supply ships and auxiliaries hid in Coron Bay, a maze of limestone islands west of mainland Palawan, thinking terrain would hide them from carrier air. It did not. On 24 September, Hellcats and other aircraft from Task Force 38 hit the anchorage. Fires, bombs in engine rooms, and ships settling in relatively shallow, enclosed water created the dive site that exists now.

These are war wrecks. Crew died. Treat them as graves even when the superstructure is a forest of lettuce coral and the photo looks like a theme park. No china, no bottles, no “just a valve.” Philippine heritage and salvage rules apply; so does basic decency.

The names you will hear most:

• Okikawa Maru — a large tanker, the Open Water-friendly headline because the deck is often 10–16 metres (tide moves that number), sand toward 26 metres.
• Olympia Maru — army cargo, about 137 metres long, upright, deck 18–24 m, sand 28–32 m.
• Kogyo Maru — cargo, roughly 22–34 m, known for holds and, for trained divers, interior routes.
• Akitsushima — seaplane tender, on her port side, about 22–36 m. Unique silhouette; Advanced territory.
• Irako — refrigeration / supply ship, the intact “jewel,” deck often 30–34 m, deepest parts 42–43 m.
• Lusong Gunboat and the Skeleton Wreck — shallow, broken, genuine Open Water wreck dives.

Olympia is sometimes confused with nearby Morazan Maru. Your dive centre’s slate, not a blog, is the identification that matters on the day.

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Depth and Dive Profile

Image by Martin Str

Coron is a progression. Match the wreck to the card, not the Instagram grid.

Water is tropical, often 26–31°C. Visibility on the wrecks is commonly 10–25 metres, sometimes less after weather or inside a hold. That is enough to see you are on a big ship. It is not Red Sea gin.

Irako’s sand is past the recreational 40-metre ceiling. Deep specialty covers the shallower Irako. The propeller at 43 metres is a gas-and-deco problem, not an “AOW extra.” Nitrox helps no-stop time on 30-metre wrecks. It does not make 43 metres legal on a recreational card.

How those numbers sit against PADI limits is in how deep you can scuba dive.

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Accessibility: Boats, Season, and the Bay

You base in Coron town (Busuanga). Wrecks are banca or speedboat runs into the bay and toward the mouth where Irako lies. Some days are short. Irako is a longer, more weather-sensitive run. There is no shore dive onto Irako.

November to May is the usual dry-season preference. Rainy months still run boats; vis and cancelled Irako days are the trade. Coron is a tropical island: build slack into a wreck-focused week.

You dive with a local operator. There is no Scapa-style permit board for visiting recreational divers, but wrecks are protected. Follow the brief. Some interiors are simply not run for untrained guests — pick that shop.

Barracuda Lake is the famous non-wreck: inland, thermocline, brackish. It is a superb contrast dive. It is not Coron wreck diving. Do not skip the fleet because the lake photographs well.

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Skills and License Required

Open Water (18 m): Okikawa Maru deck, Lusong, Skeleton Wreck, maybe a conservative Olympia deck. Stay outside. If a shop offers “OW Irako,” decline.

Advanced Open Water (30 m): Olympia, Kogyo, Akitsushima, Okikawa’s hull. This is the card that makes a Coron wreck week exist. Be current. Silt and boats are not pool skills. The Advanced Open Water guide is the course; a few warm wreck exteriors are the practice.

Deep specialty (40 m): Irako’s working depths. Without it, do not book Irako as the reason for the trip.

Wreck specialty: For holds, engine rooms, and anything where the sun is not a straight line to the surface. Coron is famous for shops that will take untrained divers inside. That is a reason to change shops, not a reason to skip wreck diving certification.

Lights, a cutting tool you can reach, and buoyancy you would trust in a cave-adjacent silt cloud are more important here than a new camera. Many Coron wrecks still fish with nets and line.

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What You Will See

On Okikawa you see scale and coral: a tanker deck that Open Water divers can actually use, batfish, lionfish, the feeling of a ship without 30 metres on the computer.

On Olympia and Kogyo you see upright cargo ships, holds, growth that has turned steel into reef. Trained divers talk about interior cargo and machinery. Untrained divers should talk about the exterior silhouette and the fish.

Akitsushima is the odd one: a seaplane tender on her side, a shape you do not get on a standard freighter. Advanced, overhead sections, easy to get ambitious.

Irako is the intact supply ship: grouper, jacks, sometimes a ray, a deck that still reads as a ship at 30-plus metres, and penetrations that belong to people with gas, line, and training. Current at the mouth of the bay is part of her reputation.

All of them can hold silt. Frog-kick or don’t go in. For comparison with another warm-water single wreck that is not a war grave, see Cozumel wreck diving. For a Red Sea cargo icon, Thistlegorm.

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How to Dive It

Brief the actual wreck, not “Coron.” Depth, current, and whether interiors are on the plan should be specific. Descend on the shot or the agreed line. Buddy close — 15-metre vis on a 140-metre hull is a place to lose people.

Turn on gas. Irako especially eats no-stop time. Do not “just swim to the stern” at 34 metres with 80 bar.

Penetration: specialty, reel, lights, no silting the team behind you. If the centre’s marketing is “we go inside every wreck,” and you do not have the card, you are not on the right boat.

War-grave manners: look, photograph, leave. Scuba diving safety still applies when the water is 30°C.

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Practical Logistics

Fly to Busuanga (USU) via Manila. Stay in Coron town. Book a wreck-focused centre, not only a fun-dive shop that does Siete Pecados and one shallow wreck. Ask which wrecks they ran last week for Open Water versus Advanced versus Deep. Ask about nitrox fills. Ask whether wreck specialty courses run on Okikawa or Olympia — that is a better souvenir than a lump of coal from a hold.

A week is the right unit. Two days is a tease: you will see a gunboat and maybe Okikawa and leave thinking Coron is “the easy Truk.” It is not. Irako and Akitsushima need the rest of the week and the right weather.

Bring a torch, DSMB, computer, and a reef-safe approach to the coral that now is the wreck. Rental gear is available; a well-fitting wetsuit still matters at 34 metres even in the tropics.

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Final Thoughts

Coron wreck diving is the Japanese supply fleet of 24 September 1944: Okikawa for Open Water decks, Olympia and Akitsushima for Advanced, Irako for Deep and for people who already wreck-dive, gunboats for a first overhead-free look at war steel.

Stay outside without a wreck specialty. Do not take anything. Do not let a cheap package talk you onto Irako with an 18-metre card. Then Coron is what the photographs promised: a bay full of ships, still there because enough divers treated them as history.