Dive the Koho Maru 5 Pak1 – The Legendary Deep Wreck in the Gulf of Thailand

The Koho Maru 5 Story – A Wreck with Three Lives

Koho Maru 5 Pak1 is one of the most exclusive and technical dive sites near Koh Chang. This Japanese gas tanker, originally owned by the PAK Line, sank on August 25, 1996, during a heavy storm. Of the 10 crew members on board, only 3 survived. Today, the wreck rests at a depth of 42 meters in the Gulf of Thailand and is one of only two shipwrecks in the world known to have once stood vertically on the seafloor.

Phase 1: The Vertical Wreck (1996–2001)

On the night of August 25, 1996, the PAK-1 went down in a fierce storm roughly 50 kilometers west of Koh Chang, on its way to Vietnam. Most of the ten crew members sleeping in the stern cabins did not survive; three men near the bow made it out. The vessel settled in a position that had never been seen before: stern on the seabed at 60 meters depth, bow pointing straight up with just 5 meters of water above it. In the surrounding waters visibility sometimes exceeded 50 meters. Word spread fast, and for nearly six years divers from across the world made the trip to Pattaya just to dive this standing tanker — one of the rarest dive experiences ever documented.

Phase 2: The Drifter (February 2001)

In February 2001, without warning, the gas that had kept the wreck upright shifted — and instead of settling flat, the ship re-floated. The bow broke the surface by about six meters and the tanker began drifting with the currents toward Cambodia. Divers on the final liveaboard trips witnessed something unrepeatable: descending beneath the stern at 50 meters and looking up along the entire length of the keel all the way to the sky above.

Phase 3: The Current Wreck – Off Mae Phim Beach (2001–today)

With the PAK-1 adrift in active shipping lanes, the Thai Navy moved in. Two tugs and a naval escort dragged the vessel south to a designated area off Mae Phim Beach, Rayong Province. The re-sinking proved difficult: only one of four explosive charges fired on the first attempt, blasting off a 300-ton LPG tank and briefly lifting the hull higher out of the water. After considerable work both tanks were finally removed and the ship was settled on the seabed — where it has remained ever since. The wreck's aft section still shows patches of its original white paintwork. Today, GPS: N 12°05′32.5″ / E 101°40′56.7″.

Dive Conditions

Parameter	Details
Depth – deck	approx. 25 m
Depth – seabed	42 m
Thermocline	typically 25–35 m (variable)
Visibility above thermocline	up to 30 m+
Visibility below thermocline	1–3 m (torches mandatory)
Recommended gas	Nitrox 28 (twin set + deco cylinder)
Bottom time (inside)	45 min+ with twin set and deco

Note on penetration: The aft section offers extensive swim-throughs and penetration options. Silt disturbance can instantly reduce visibility to zero — reel off before entering the holds and never dive this site without proper technical wreck training and a redundant gas plan.

Why Dive at Koho Maru 5 Pak1?

• Legendary Deep Wreck: Experience one of the rarest wreck diving experiences as the Koho Maru once stood vertically underwater.
• Technical Diving Challenge: This dive requires technical diving skills, with a depth of 42 meters and strong current possibilities.
• Historic Wreck Adventure: Discover a shipwreck with a fascinating past and explore its cargo holds, control rooms, and structures.

Dive Site Overview

Max Depth	Type	Marine Life
42 meters	Technical Wreck Dive	Grouper, barracuda, moray eels, lionfish, reef fish

Ready for a deep diving adventure? Join us on a rare expedition to the Koho Maru 5 Pak1 Wreck. Book your technical diving course of fun dive with Chang Diving Center today!

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Diver Level for this dive site.

Min. certification level: NITROX-, Deep-, Wreck or Technical Diver (or equalled) Try Diving possibility: No Snorkelling possibility: No

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Our Divemaster's

Our Divemasters will give you a boat briefing and an overview for the day at the time the boat starts. They will give you a Dive briefing before each dive, and be in the front to lead the group while diving. Ask you frequently for Air consumption and knock against the Tank to get your attention. If there is any problem they will assist you, to secure your and others safety. If you and your buddy would like to explore the dive-site yourself the Divemasters will give you a briefing on the boat and check the predive safety procedure before your buddy team enter the water.

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Entry and Exit

Dive Boat

Predive Safety Check! We enter the water from the side of the Boat with a Giant Strike, if all is OK, clear the place and swim on the surface to the starting point. After the dive, back on the surface we swim back to the ladder on the side of the boat, stand on the ladder and take off the fin's (give it up to the crew) climb up the ladder with the regulator in your mouth. Never stay under a diver which try to climb up.

Dinghy Boat

Predive Safety Check! We enter the water with a backroll entry. When everything is OK, clear the place and swim on the surface to the starting point. After the dive, back on the surface, we swim back to the dinghy boat. When you reach the dinghy boat remove your weight belt and BCD. Start to get up the dinghy with the help of a few kicks with your fin's.

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Dive Procedures

• Review the necessary Handsignals for scuba diving.
• What you maight spot while diving or snorkelling
• When you end any dive a safety stop on 5 m of depth for 3 min is recommended.

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Emergency Procedures

• Police, Phone: 191
• Tourist Police, Phone: 1155
• EMS, Phone: 1669
• DAN International, Phone: +1-919-684-9111
• Suspicion of DCS
• Recrompression chaimber, Koh Chang Hospital, Phone: 039 521-657 or 039 586-131

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What other divers discovered

Real reviews and experiences from our guests – see what others found on their diving adventures with us!

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More Wreck Dives

Explore more wreck diving adventures around Koh Chang. These historic wrecks offer fascinating underwater exploration and abundant marine life.

Straight Talk: Wreck terms on Koh Chang (HTMS Chang focus) —swim-through vs light-zone and full overhead in plain language.