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Diving HTMS Chang and Alahambra Rock

HTMS Chang is Thailand’s biggest shipwreck, and it’s now an awesome sanctuary for marine life too. Coupled with Alabambra Rock, it makes for a great weekend’s diving

Yellow snapper over the coral encrusted HTMS Chang wreck, Thailand
Yellow snapper over the coral encrusted HTMS Chang wreck © Chris Mitchell

HTMS Chang was sunk off the Thai island of Koh Chang in the Gulf of Thailand back in 2012. A former American World War 2 tank landing ship, it was turned over to the Royal Thai Navy in 1962 and when it reached its end of service, it was cleaned up and then scuttled to create an artificial reef and new dive site for its namesake island.

Flag on the mast of HTMS Chang, Thailand
Flag on the mast of HTMS Chang, Thailand © Chris Mitchell

My friend Joe of BK Dive Crew had explained to me how good a dive the HTMS Chang wreck was in a podcast we did together, which had piqued my interest. Instead of making the journey from Bangkok to Koh Chang and diving the wreck from the island (it’s a half hour boat ride from Koh Chang – every dive shop goes there), we decided to get a liveaboard from Rayong which departs Friday night and is back Sunday afternoon – perfect for Bangkok weekend divers.

As we were diving in March 2021, Thailand had shut its borders due to Covid but domestic travel was still possible. While the liveaboard was full, we were the only boat on the wreck during our day of dives there.

Crow's Nest on the HTMS Chang wreck
Crow’s Nest on the HTMS Chang wreck © Chris Mitchell

The HTMS Chang sits upright in the water and the descent is by the conning tower and wheelhouse, so you can see the ship appear into view as you drop further down. The viz wasn’t that great, about 5 metres, but it wasn’t awful either – as it often the case with the wrecks in Pattaya.

What’s immediately apparent as you pass the crow’s nest and bridge descend to the deck is the awesome dynamic swirl of hundreds of juvenile barracuda and yellow snapper schooling around the conning tower. They are so numerous it’s often hard to see the wreck anymore as you navigate around it. The wreck is now an important haven for marine life and also effectively a huge nursery, providing shelter for younger fish to mature.

Snapper through the HTMS Chang wreck
Snapper through the HTMS Chang wreck © Chris Mitchell

HTMS Chang is the biggest shipwreck in Thailand, and the deck is at around 23 metres, so to get all the way around it in one dive is probably not the best way to go, especially if the viz is poor. For me the best photo opportunities were around the central tower – which itself takes a while to navigate fully around – so we didn’t spend much time at the bow or the stern given the mediocre viz.

Even though it’s only been down for 9 years, the wreck is already encrusted with coral – and plenty of sea urchins. There is also quite a lot of macro life living in nooks and crannies of the wreck too. While the snapper provide the initial unmissable wow factor, all sorts of smaller life have been found here from frogfish to seahorses. Whale sharks have been known to show up at the wreck each season too.

Cross beams, HTMS Chang wreck, Thailand
Cross beams, HTMS Chang wreck, Thailand © Chris Mitchell

Penetration of the cargo holds at 28 metres is possible if you’ve the correct training – we left that alone. There’s no tanks still on board the ship, unfortunately.

The Chang is big enough to repay repeated dives and I wish we’d had another day to explore. Check Google Images and you’ll find lots of pix of the ship taken in better viz where its sheer size becomes apparent.

Turtle at Alahambra Rock, Thailand
Turtle at Alahambra Rock, Thailand © Chris Mitchell

The following day we did two dives at Alhambra rock on the way back to Rayong. This is a large sea mount that is absolutely covered in hard corals and also acts as a magnet and protective zone for marine life.

Whip coral, Alahambra Rock, Thailand
Whip coral, Alahambra Rock, Thailand © Chris Mitchell

The viz wasn’t great but it was good enough to to see a turtle in the shallows and appreciate what good shape the coral was in. Search on YouTube and there’s video footage of big schools of fish hanging around Alahambra Rock and I’d imagine barracuda like it too. Whale sharks have also been seen here.

Clownfish and diver, Alahambra Rock, Thailand
Clownfish and diver, Alahambra Rock, Thailand © Chris Mitchell

In all, it was an impressive weekend’s diving, and with the added bonus of being able to get to and from Bangkok within a weekend. Without the Liveabaord we wouldn’t have seen Alahambra Rock which was a great spot. Day trips run out to it from Rayong so it’s a relatively easy site to access.

Big school of yellow snapper, Alahambra Rock, Thailand
Big school of yellow snapper, Alahambra Rock, Thailand © Chris Mitchell



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My Recent Dive Trips

  • November 2024: Similan Islands liveaboard, Thailand
  • October 2024: Forgotten Islands and Banda Sea liveaboard, Indonesia
  • August 2024: Komodo and Saleh Bay liveaboard, Indonesia
  • May 2024: Similan Islands liveaboard, Thailand
  • April 2024: Sogod Bay, Philippines
  • February 2024: Similan Islands liveaboard, Thailand
  • January 2024:Gangga Island Resort, Indonesia
  • December 2023: Similan Islands liveaboard, Thailand
  • Mejangan Island, Bali
  • October 2023: Similan Islands liveaboard, Thailand
  • June 2023: Raja Ampat liveaboard, Indonesia
  • April 2023: Maldives liveaboard
  • April 2023: Similan Islands liveaboard, Thailand
  • February 2023: Similan Islands liveaboard, Thailand
  • December 2022: Raja Ampat liveaboard, Indonesia
  • December 2022: Similan Islands liveaboard, Thailand
  • August 2022: Komodo liveaboard, Indonesia
  • June 2022: USAT Liberty shipwreck, Bali, Indonesia
  • April 2022: Stonehenge, Koh Lipe, Thailand
  • March 2022: Manta Rays at Koh Bon, Thailand
  • January 2022: Richelieu Rock liveaboard, Thailand
  • March 2021: HTMS Chang and Alahambra Rock liveaboard, Thailand
  • February 2020: Similan Islands liveaboard, Thailand
  • December 2019: Raja Ampat liveaboard, Indonesia
  • October 2019: Malapascua, Philippines
  • June 2019: Sogod Bay, Philippines
  • April 2019: Tulamben, Bali
  • December 2018: Sogod Bay, Philippines
  • December 2018: Anilao, Philippines
  • October 2018: Moalboal, Philippines
  • October 2018: Malapascua, Philippines
  • July 2018: Tulamben, Bali
  • May 2018: Raja Ampat, Indonesia
  • April 2018: Sogod Bay, Philippines

My Less Recent Dive Trips

  • May 2017: Apo Island and Dumaguete, Philippines
  • April 2017: Tubbataha Reef, Philippines
  • April 2017: Sogod Bay, Philippines
  • March 2017: Triton Bay, Indonesia
  • March 2017: Raja Ampat, Indonesia
  • September 2016: Tulamben, Bali at Alba Dive Resort
  • August 2016: Cenderawasih Bay on Damai 1
  • April 2016: Sogod Bay at Sogod Bay Scuba Resort
  • February 2016: Raja Ampat and Banda Islands on Damai 1
  • April 2015: Anilao at Crystal Dive Resort
  • March 2015: Myanmar and Similan Islands on Thailand Aggressor
  • May 2013: Similan Islands on Thailand Aggressor
  • April 2013: Tubbataha Reef on Discovery Palawan
  • January 2013: Komodo, Indonesia on MSY Damai
  • August 2012: Cenderawasih Bay, Indonesia
  • April 2012: Similan Islands and Southern Thailand liveaboard
  • January 2012: Similan Islands liveaboard, Thailand
  • August 2011: Hanifaru, Maldives
  • June 2011: Tubbataha Liveaboard Hans Christian Andersen
  • April 2011: Similan Islands and Southern Thailand liveaboard
  • April 2011: Carpe Vita Liveaboard, Maldives
  • March 2011: Lembeh Strait, Indonesia
  • December 2010: Menjangan, Bali
  • July 2010: Tofo, Mozambique
  • July 2010: Sardine Run, South Africa
  • May 2010: Sangalaki / Derawan, Tambora
  • March 2010: MV Flying Seahorse, Similan Islands
  • March 2010: MV Orion, Southern Maldives
  • January 2010: Big Blue Explorer, Palau
  • November 2009: MSY Damai, Banda Sea Liveaboard, Indonesia
  • October 2009: MSY Damai, Komodo Liveaboard, Indonesia
  • October 2009: MV Orion, Maldives Liveaboard
  • September 2009: MV Scubanet, Koh Losin, Thailand
  • May 2009: MSY Seahorse, Banda Sea liveaboard, Indonesia
  • March 2009: Sachika Liveaboard, Maldives
  • February 2009: Daytrips, Koh Lanta, Thailand
  • January 2009: MV Jazz, Burma (Myanmar) Liveaboard

Back In The Day Bragging Rights Dive Trips

  • November 2008: Borneo Explorer, Visayas Liveaboard
  • September 2008: S/Y Siren, Komodo Liveaboard
  • August 2008: Ocean Rover, Sulawesi Liveaboard
  • August 2008: NAD Lembeh Resort, Indonesia
  • June 2008: Koh Tao
  • March 2008: Maldives, Bandos Island
  • February 2008: MSY Seahorse, Raja Ampat Liveaboard
  • January 2008: MV Jazz, Burma Liveaboard
  • October 2007: Bali Dive Safari
  • September 2007: Davao, Philippines
  • July 2007: Great White Sharks, Rodney Fox Liveaboard
  • June 2007: Big Blue, Palau Liveaboard
  • May 2007: Whale Sharks at Exmouth, Australia
  • April 2007: Borneo Explorer, Tubbataha Reef Liveaboard
  • December 2006: Komodo Dancer, Komodo Liveaboard

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