Pioneer Wreck
Also known as: Mogami Maru, Oakita Maru, Pioneer, Unknown Maru
An upright Japanese wreck of the Second World War 6 km north of Malapascua, deck at 46 metres and seabed at 56, on staged decompression.
Last updated August 2026
The dive
Ten minutes out of Bounty Beach the boat stops over water with nothing in it. No mooring, no shot line: the descent is free and blue, and the wreck does not resolve until around 40 metres1.
What finally shows up is small and legible. The bow is whole, both anchor windlasses in place with the chain still running down from them. Behind that the midships has folded in on itself where the wheelhouse stood, and the helm is long gone. The cargo hold is open, oil drums and electrical parts still lying in it. An anti-aircraft mount lies collapsed. The stern is torn away, and the propeller sits half buried in the sand beside the damage2.
She is a war grave. The remains of her crew are aboard, and nothing here is touched, moved or lifted.
Then the long part. Every minute spent on the hull is bought back in decompression, and the ascent is the same empty water as the descent, hung under a bag with nothing to look at.
What makes it special
Everything else dived from this island is inside recreational limits, including the other three wrecks, the deepest of which ends around 33 metres. This one starts below 40 and that single fact runs the whole site. No recreational boat comes here, and the wreck holds more fish than anywhere else off Malapascua because of it3.
The other thing is that nobody has closed the name. Every other wreck in the area has one that people agree on. This one is sold under two, by centres working off the same beach, and on the day she sank those two ships were logged 115 kilometres apart.
History and origin
Carrier aircraft from Task Force 38 opened three days of strikes on the Visayas on 12 September 1944, and this ship went down in them4. The date is the one part of her identity nobody argues about.
The name on the boat schedule is not hers. The site was called after the Cebu Pioneer, a 55 metre ferry lost off Malapascua in a typhoon in 1966, and that ferry turned up in 2012 at 110 to 115 metres, far below anything dived from here2. Two Japanese names are published for the wreck itself. That morning a transport called Oakita Maru was logged sunk three kilometres from this position, and the Mogami Maru was logged with a group of small auxiliaries 115 kilometres south, off Cebu City4.
The same year the ferry was found, an expedition filmed this wreck for national television. The coral growth dated her to the war, and the sketches and video were matched to a photograph of the Tokachi Maru, described as an exact replica and sister vessel of the Mogami Maru5. A sister ship identifies a class, not a hull.
That expedition ran for a reason that has not gone away: Malapascua's wrecks were being cut up for their steel, and an unnamed wreck is easier to cut up than a named one5. Things have already left this one. The helm went to a dive shop2, and a 78 rpm record came up with its Japanese label still legible1. Nothing else should follow them. Cultural property found in an underwater archaeological site belongs to the State under Philippine heritage law6.
Know before you go
Decompression training is what centres here ask for, and technical certification is published as the requirement2. Nobody publishes a gas rule, so the mix is your team's decision, and the arithmetic is not ambiguous. EAN32 runs out at about 34 metres, above the highest point of the wreck. Air at the seabed sits at its working oxygen limit with narcosis equal to the full depth. What that leaves is a helium bottom mix and staged decompression, which is how the people who run the dive plan it1.
A torch earns its place here, which is not true of most diving around Malapascua: there is an interior, and it starts below 45 metres. Nothing is moored either, so an SMB and reel belong in the plan rather than the contingency bag. Most of the runtime is mid-water.
The site goes only when the tides are right3, so expect the day to move and keep a shallower wreck on the list.
Malapascua has nowhere to treat a bent diver, and this is the one dive off the island where that belongs in the plan rather than in a footnote. Treatment means Mandaue: first the crossing, which the coast guard closes as the afternoon goes, then three or four hours by road. The nearest hospital on the mainland is graded an infirmary. That argues for more gas than the runtime needs, more redundancy than feels necessary, and an early start.
Why Dive Pioneer Wreck
What makes this dive site stand out.
- Deck at 46 metres
The shallowest structure sits at 42 to 47 m and the sand under her at 52 to 56 m
- Two published names
Sold as both Mogami Maru and Oakita Maru, and neither has been proved
- Upright and largely whole
Intact bow, open hold, a collapsed gun mount and a stern torn away by the attack
- Decompression with no chamber
Deco is the plan here, and the nearest working chamber is a crossing plus hours of road
- A war grave
The remains of her crew are aboard and nothing on her is moved or taken
Depth & Profile
Location
11.3750°N, 124.1067°E
Conditions & difficulty
Summary
Depth, a mandatory decompression obligation and a real overhead, with no shallow version of the dive. The top of the wreck is deeper than most divers have ever been.
Safety considerations
What can go wrong here, and what divers do about it. Conditions change - take the briefing from the operator on the day.
- Depth: The shallowest structure is 42 to 46 m and the sand 52 to 56 m, so every point of the dive is past recreational limits and standard nitrox mixes are unusableA helium bottom mix, staged decompression and technical certification. There is no recreational version of this dive
- Depth: Every minute on the hull incurs a decompression obligation that is discharged in open water with no referenceRedundant gas and computers, an SMB and reel, and a runtime agreed on the boat before anyone gets in
- Overhead: The openings lead into a collapsed midships and a bombed engine room at 46 m and below, inside a hull that has been on the seabed for eighty yearsTechnical wreck training on top of the decompression certification, plus line, redundant light and gas reserved for the overhead
- Structure and sharp edges: Bomb-damaged plating, a torn stern and collapsed deck sectionsStay off the structure and keep trim; damaged plate is not something to steady yourself on
- Current: The site is tide-gated and no figure is published for how hard it runsTake the operator's call on the window and do not push a marginal tide
- Remote location: Open water 6 km off the island with no mooring, on a profile where an omitted stop is a chamber case by definitionConservative runtimes, dive insurance, and ask what emergency oxygen the boat keeps aboard before you book
Regulations
No ordinance sets a fee for this site and operators price technical trips individually, so confirm what a decompression dive includes when you book.
Frequently Asked Questions
What ship is the Pioneer wreck at Malapascua?▾
Nobody knows, and the two answers in circulation come from the same wartime loss list. On 12 September 1944 carrier aircraft sank a long line of Japanese shipping across the Visayas, and the positions were written down ship by ship. A transport called Oakita Maru was logged at 11 degrees 21 minutes north, 124 degrees 07 minutes east, about three kilometres from this dive site. The Mogami Maru was logged the same day among a group of small auxiliaries at 10 degrees 20 minutes north, 124 degrees 00 minutes east, roughly 115 kilometres south in the approaches to Cebu City. The position fits one name, the hull form fits the other, and neither is proof. No registry entry, survey report or maker's plate has ever been produced for this hull.
Is the Pioneer wreck the same as the Cebu Pioneer ferry?▾
No, and the two have been known to be separate since 2012. The Cebu Pioneer was a 55 metre passenger ferry lost off Malapascua in a typhoon in 1966. She was located in 2012 lying on her keel at 110 to 115 metres, which is trimix exploration territory and not a dive anyone sells. The site called Pioneer is a Japanese vessel of the Second World War sitting between 42 and 56 metres, six kilometres north of the island. The name stuck to the wrong wreck and the boat schedules never changed it back.
How deep is the Pioneer wreck?▾
Both figures you will see are right. The deck is at 46 to 47 metres and the seabed she sits on is at 52 to 56, so a page quoting 46 and a page quoting 55 are describing the top and the bottom of the same ship. The shallowest structure has been reported as high as 42 metres. Tide accounts for part of the spread at the deep end. The number that matters for planning is the seabed one: at 56 metres air is at its working oxygen limit and the decompression obligation is not optional.
Do you need trimix to dive the Pioneer wreck?▾
No centre here publishes a mix as a rule, so treat this as the profile talking rather than a shop requirement. EAN32 has a maximum operating depth of about 34 metres, which is shallower than the highest point of the wreck, so standard nitrox is unusable anywhere on the site. Air at 52 to 56 metres puts inspired oxygen at the working limit with narcosis equal to the full depth. What centres do require is decompression training, and divers who run the site here describe four cylinders and multiple gas mixes. Plan it with your team and your instructor, not from a web page.
Can you penetrate the Pioneer wreck?▾
Partly, and the ship's size limits it more than discipline does. Much of the damaged area is open and easily entered, but the hull is small enough that no extensive penetration is possible. Take the strict reading anyway. The overhead is a collapsed midships and an engine room that took heavy damage, at 46 metres and deeper, in a structure that has been corroding since 1944. That needs a technical wreck qualification of its own, on top of the decompression certification the dive already demands. Open is a description of the doorways, not permission to use them.
When can you dive the Pioneer wreck?▾
Only when the tides are right, which is the operator's call and not a fixed schedule. Which state of the tide opens the window, and how long it stays open, is not something anyone states, so this is a dive that moves and occasionally does not happen at all. Ask when you book, ask again the night before, and keep a recreational alternative on the list.
What happens if something goes wrong on the Pioneer wreck?▾
You are a long way from treatment, and that is the single most useful thing to know about this site. Malapascua has no working recompression chamber. Treatment means the hyperbaric unit at Mandaue City, reached by a boat crossing the coast guard closes in the late afternoon plus a road transfer of three or four hours, and the district hospital on the mainland is classed as an infirmary rather than a critical-care centre. On a dive where decompression is the plan rather than a contingency, an omitted stop is a chamber case by definition. That shapes gas reserves, redundancy, how conservative the runtime is, and what time of day you get in the water.
References
- 1.Evolution Diving Resort (Matt Reed), October 29, 2013 — The Mogami Maru Revisited
- 2.Evolution Diving Resort — Wreck Diving in Malapascua
- 3.Thresher Shark Divers — Malapascua Dive Sites: Wrecks
- 4.Naval Historical Center (Robert J. Cressman), September 12, 1944 — The Official Chronology of the U.S. Navy in World War II, entry for 12 September 1944
- 5.GMA News Online, October 30, 2012 — History at 52 meters deep: The shipwrecks of Malapascua
- 6.Republic of the Philippines (WIPO Lex record), March 26, 2010 — Republic Act No. 10066, National Cultural Heritage Act of 2009
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