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Diving the Boonsung Wreck: The Fish Soup of Khao Lak

There’s nothing more magical than descending a buoy line and seeing a structure materialize out of the blue. The Boonsung wreck offers that very experience.

Some of the greatest underwater allures for divers are the wrecks scattered throughout our oceans. There’s nothing eerier or more exciting than descending a buoy line and seeing a structure materialize out of the blue. Worldwide diving hotspots each seem to have their own marquee wreck, and Thailand is no different. One of the best wrecks in these waters is the Boonsung in Khao Lak.

Khao Lak is situated on the west coast of Thailand, along the shores of the Andaman Sea. This small village is the starting point for many liveaboards and day trips to the Surin and Similan Islands. And just 3 miles (5 km) off the coast is the Boonsung wreck, a must-dive when visiting the area.

A brief history of the Boonsung

Khao Lak and the surrounding area was part of Thailand’s once-booming mining industry. The Boonsung was a tin dredger in its heyday until sinking sometime between the late 1970s and early 1980s — dates vary depending on the sources, with most pointing to 1983 or 1984.

There is much speculation as to why it went down. Urban legend has it that someone flushed a faulty toilet, causing water to rush in. Some claim it was deliberately sunk for easy and cheap disposal. Whatever the reason, the Boonsung came to lie on the ocean floor.

Being close to the surface, however, the wreck was a hazard to shipping. Consequently, the Thai Navy detonated a few bombs to level it out. This, combined with damage caused by the 2004 tsunami, has left the wreck looking nothing like a ship.

The perfect fish haven

With nothing but sand for miles around, the Boonsung quickly became an artificial reef and a haven for thousands and thousands of fish and other species. This high density of marine life is better than many dive sites in the Similan Islands and has lead divers to describe the Boonsung as a ‘fish soup.’

As you descend one of three lines, you will immediately see why. Huge schools of snappers, trevally, fusiliers, barracuda, and batfish await. Porcupine and pufferfish gather in large numbers, as do lionfish and squid. Moray eels emerge from every crevice. Divers should look out for scorpionfish, crocodilefish, and bluespotted stingrays in the sand. The Boonsung wreck and its surrounds simply teem with wildlife. You may even spot the occasional whale shark cruising past.

Macro marine life

Despite all the larger animals, the variety of macro marine life truly makes the Boonsung unique. Since most dive centers do two dives on the wreck, it’s the perfect excuse to move slowly and search for the small wildlife. Ornate ghost pipefish and frogfish live side-by-side with numerous species of nudibranch. One part of the wreck has even been renamed the “nudi hotel” thanks to the vast numbers living there.

Look closely for the countless holes in the sand where gobies keep guard while their shrimp housemates work tirelessly to maintain the cohabited burrows. Also a treat are the honeycomb morays that have made the Boonsung their home. You’ll rarely see these beautiful eels at other dive sites, but here you’re pretty much guaranteed a sighting of both adults and juveniles.


Although it no longer resembles a ship, the manner in which the Boonsung has broken up into four main structures makes for a very interesting dive site. The wreck lies at 60 feet (18 m) on a flat, sandy bottom. Because of the damage, the shallowest part sits at around 36 feet (11 m) with the average roof level at 43 feet (13 m).

The only disadvantage of diving the Boonsung wreck is the visibility, which usually hovers around 33 feet (10 m). However, after descending, navigation is simple. Heading in a clockwise or counterclockwise direction, move between the four broken-up sections. Stay close to the wreck and you won’t get lost.

Unfortunately, the wreck’s structure has become unstable since the 2004 tsunami, which means divers are not allowed to penetrate the wreck. But with so much to see and explore on the outside, there’s plenty to keep you occupied.

Diving conditions

Apart from the somewhat reduced visibility, there aren’t a lot of environmental concerns. There is no significant current to deal with, which is why it’s such a good wreck to explore at a leisurely pace.

Divers should, as always, pay attention to their buoyancy. Because it’s a wreck, the Boonsung has sharp metal hazards throughout. Watch for scorpionfish, stonefish and black sea urchins as well. Divers will need good buoyancy to avoid contacting anything they shouldn’t.

Who can dive the wreck?

The Boonsung is a great dive for everyone, as there’s something here for every skill level. It’s a straightforward dive with minimal current, making it an ideal first wreck dive for beginners. The flat, sandy bottom and shallow depth also make it suitable for open-water and advanced open-water students.

Seasoned divers will not be disappointed with two dives on the Boonsung, either. Exploring the nooks and crannies around the wreck will reveal the huge variety of macro life that lives here. The Boonsung will keep even the most experienced diver happy.

When to dive the Boonsung

Khao Lak has a tropical climate and is warm year-round. The best time for diving here is between October and May, as this is out of the monsoon season. It’s possible to visit the Similan islands as well during this time. When the southwest monsoons arrive, the Andaman Sea can get quite rough. Although centers still offer trips to the Boonsung, they are often canceled due to inclement weather conditions.

Peak season is December and January when Khao Lak is crammed with tourists and divers alike. Avoiding these months means fewer tourists and the calmer water, a double bonus in any diver’s mind, so you might prefer to visit outside of the hectic high season.

Although the Boonsung is a great dive, it’s even better when you can enjoy the ‘fish soup’ with no other divers around. October to May is also the best time to see whale sharks. Who knows, you might just combine wreck diving with a sighting of this giant of the sea.