Samaesan Hole

The Samaesan Hole is infamously regarded as one of the most dangerous dive sites in the world. Divers will require advanced planning and technical skills to manage the risks associated with this extreme dive site.

DIVE SITE LOCATION

The Samaesan Hole dive site is located in the Gulf of Thailand, Koh Samaesan, in Sattahip District, Chonburi Province. It lies in the vicinity of the shipping lanes between Koh Rong Nang and Koh Samaesan by the area named “Explosives Dumping Ground” on local sea charts.

 

DIVE SITE HISTORY

The dive site is the deepest in the Gulf of Thailand (85-100m) and first dived in 1998 by local dive legend Steve Burton & Claes Martinsson, who referred to it as the “black silty hole of death”. The Samaesan Hole has gained notoriety as one of the most extreme and hazardous open water dive site in the world due to its depth and challenging conditions. It commonly features on lists of the top ten most dangerous dive sites in the world and is the only open water dive to ranked in Red Bull’s Most Extreme Scuba Dive Locations.

 

ABOUT THE DIVE SITE

The Samaesan hole is a steep-sided underwater crater which light does not penetrate. These dark conditions are compounded by the poor visibility (which typically ranges from 5-10m), reducing the effectiveness of your light at depths below 60m. Currents are typically strong and unpredictable, including down currents and vortex than can swirl you around underwater. There is little marine life apart from soft coral although I have spotted a lone Puffer Fish and a couple of sleeping Ray over my years of diving here.

Samaesan Hole: Map
Location: 12°32.314′N, 100°57.616′E

Samesan Hole – Hazards

  • Depth: The Samaesan Hole decends down to 85-100m at its deepest part. Hypoxic Trimix is therefore a recommendation for most divers. At these depths, deep air divers will have potentially debilitating nitrogen narcosis to manage as well as closely having to closely monitor for Ox Tox.
  • Visibility: Be prepared for poor visibility (5-10m) throughout the dive. 
  • Darkness: Light does not typically reach below 60m at this site. At the deepest parts the water is an inky black, with turbidity limiting whatever reach your primary light has. Bring a back up torch!
  • Strong Currents: The area has some of the strongest and unpredictable currents in the gulf of Thailand. So if you get your timing wrong you could end up in Pattaya or Cambodia depending on if the tide is rising or falling. Check the tides times before you go as there are only few days each month where tidal conditions (on paper) are ideal. Observing the whip corals on the bottom is a good indication of current strength and if you are getting dragged down deeper in to the hole. Ensure that you have a vigilant boat captain that will look out for and follow your DSMBs otherwise there is a very really chance you will be lost at sea.
  • Down Currents: The strong currents do not just push you along – they will also pull you down. So watch your depth and ascent/descent to make sure you do not overshoot your planned depth or are getting dragged back down during your ascent. If during the dive the water suddenly becomes murky it is generally advised to start your ascent immediately. Ensure a wing with sufficient lift and that you have redundancy.
  • Vortex: In addition to being dragged along and down by the current there are instances where you are  going to be spun around. This tends to be from 45m-60m range. In the black water the only reference point you have are the particles (lit up by your torch) flying past your face sideways. The risk of disorientation is high especially if narced.
  • Bombs: Displayed prominently on the local sea charts you will read the words “Explosives Dumping Ground”. That’s right! The Samaesan Hole is used to dump unused ordinance. With the bombs littering the sea bed it is highly advised that you maintain a controlled descent.
  • Shipping Lane: Even if you have successfully managed to get out of the hole your problems may not be over as the dive site is in the middle of a busy commercial shipping lane. It is common to see large LPG vessels crossing the site on their way to/from Rayong. The hulls on these vessels stretch down to your last 4 deco stops so always worth looking on the the horizon before getting in the water.
Samaesan Hole: commercial shipping lane
LPG Shipping Container passing by the Samaesan Hole

HOW TO DIVE HERE

The site is only accessible by boat, which is roughly a 40min trip from Chong Samaesan where most of the dive operators moor their boats. Dive operators for this site are typically based in Pattaya so if you are wanting to dive here then this is a good starting point for finding shops.

 

Due to the number of hazards associated with this site I would strongly recommend an experienced operator and Technical Dive Guide/Instructor who is very familiar with local conditions. I would highly recommend Dive Pattaya and Tec Pattaya for this due to them having a dedicated tech diving boat; gas blending & equipment maintenance facilities; and experienced TDI, PSAI and PADI Tec Instructors who regularly dive this site.

Chong Samaesan Piers
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