Southern Thailand is dotted with hundreds of Limestone Mountains and pinnacles. In this landscape of endless rock, jungles and plantations there are still many discoveries to be made. One of these places is Thailands cave Tham Phet and Tham Ya Wua Yai cave in Phang Nga province. They were originally believed to be 2 separate caves so our goal of this trip was to make the first ever traverse of these amazing caves.
The caves were partially explored and survey way back in 1987 and then again in 2001 by different European spelunking expeditions. My dear friend and fellow explorer Nico Boisard, came from France to spend a few months here to work on this and some other projects. After about half a dozen recon trips were made, it was time to mount the final assault on the full traverse.

time to get ready
The rain had stopped for a few months now, and the water levels in the caves were now low enough to attempt the first traverse. We prepared all the gear and supplies needed and set out from Krabi to Thailands caves Tham Phet and Tham Ya Wua Yai in the Thap Put district.
After reaching the hidden valley in the northern part of the district, we had breakfast, and then made the final preparations. With a satisfied stomach we set out to ascend up the mountain through its plantation’s and jungle to reach Tham Ya Wua Yai cave entrance. It was a steep 200m ascent which took about 1.5 hours. During the ascent my friend Iam Jai brushed against an unknown plant which caused his arm to itch and swell gradually throughout the day.
The last part of the walk followed a small stream, which lead us to the very large and overgrown entrance to the cave. We suited up, helmets on, lights on, and off we went into the perpetual darkness of the underworld. Going into a place like this, does not come without risk. If anything happens in here, rescue here can be anywhere from extremely difficult to impossible. So unless you have experience with spelunking and are prepared for an adventure like this, don’t attempt it.
into the underworld
The cave system has a minimum length of 1,8km and a decent of at least 200m which will be made to reach the exit. Since the cave has not been fully surveyed, this is only an estimate. After walking a 100m or so the ceiling from the cave reached some 50-60m above us. The last rays of light were disappearing behind us and now only the squeaking of the bats could be heard from the cave ceiling above us.
We were following the river as well as we could. Like all places in the underworld, it was dark, very dark, but compared to other caves it was rather a noise cave and very wet. The river took many small bends and there was one waterfall after the next. Massive boulders, canyons, tunnels, and many large chambers with high ceilings were to be found all along the way.
The rock was black and extremely slippery. Many places were also covered in wet mud, making movement difficult and dangerous. In an environment like this every step needs to be calculated and carefully placed.
Traveling through the cave system, there were fascinating formations, and even a few creatures. Though the further we went in, squeezing through holes and small passages. We came to a part where even the bats didn’t venture. Waterfall after waterfall, chamber after chamber, the darkness continued on. Words can’t describe being in a place where no one has ever been before.
Finally after a few hours we reached the crux (most difficult part) of the cave, which also meant we had been here before from the other side, and were not far from the exit. Though before we did this, we rested and had lunch.


exiting Thailands cave Tham Phet
This is the only section that required ropes, and 2 abseils were necessary. The river turned into a very narrow canyon here and a series of waterfalls. The first 2-3m, then 5m, then 15m, and then 3m again…etc…. The 5 and 15m ones were the crux. Fortunately today it was much easier. When we had climbed up from the other side, the water level was higher and the waterfall was so loud communication was very difficult.
We did It!!!!! Joy overcame us when reach ground level. We did! We connected the two caves for the first time. Now all we had left was to follow the cave for 5-800m more to reach the exit, but from here it was easy and leveled. No difficult climbing and or really dangerous sections left. A feeling of happiness, relief and satisfaction fell over the group as we walked to the light.
It took us 1.5 hours to reach the cave entrance and then another 5.5 hours to reach the exit. This was truly an awesome adventure and an awesome job Nico. This was Thailands Phang Nga cave Tham Phet and Tham Ya Wua Yai first ever traverse. Now all that is left to do is to survey the middle section and it can official be declared one cave.
We or another team will be back for this………
…read more about caves in Asia on our page Caving South Asia.
Expedition Team:
Leader: Nico Boisard, Technical Assistant: Till Jungmann, Photography: Iam Jai, Logistics: Mark Leo