I visited this WHS in Spring 2025. Having read through the quite negative reviews online balancing out the mostly national praise for this site as one of the 7 Wonders of Nature, we decided to sleep for a couple of nights at the coastal village of Sabang to beat the early morning and afternoon taxi van hairpin races shuttling visitors from Puerto Princesa to Sabang.

This decision was key to our enjoyment and better appreciation of this WHS. All visitors need to pay a combination of entrance, environmental, audio guide, mooring and boat trip fees at the very organised ticket office in Sabang. The ticket office opens just after 07:30 but officially starts registering and accepting payment at 08:00 sharp. What they do is write down a series of numbers on pieces of paper and the first one to arrive is given number 1, second number 2, etc. and then call out the number for those who were there early (we were there at around 07:00 to make sure we were first before the groups. Having exact change also helps as once you get your permits paid, you'll want to make sure you get the first motorised banka out before any groups who might be already waiting at they quay while their tour operator or guide is taking care of registration for them. When we visited the total cost was 735 pesos + 2,100 pesos for the boat ride (with minimum 6 and maximum 10 passengers). Instead of waiting and dividing the latter cost with another 4 passengers, we informed the ticket office that we wanted to pay the whole amount to depart immediately and visit the subterranean river alone. 

The ticket office is just by the quay from where all motorised bankas depart to the pretty sandy beach closest to the subterranean river. Make sure you wear insect repellent as the beach is infested with sandflies! From the beach there is a short walk through monkey territory (better avoid having any food or plastic bags visible!), where you will find one stainless steel and one colourfully painted wooden UNESCO WHS plaques. You'll also be given life jackets, helmets and an audio guide here before heading to your non-motorised banka/canoe. I'm not sure whether you can ask not to pay for the audio guide (85 pesos) but we were better off without it, as we weren't interested in the Batman and Titanic movie soundtracks and all the different shapes and imagined resemblances. The locals manually paddling you round the subterranean river in the second banka will gladly use their torches to light up the different geological formations.

Personally I really found the whole experience and lack of electricity (no Disney-like lights and/or music) really great and the sheer amount of bats and swiftlets living or flying around inside the caves clearly shows that nature is thriving here notwithstanding the high volume of visitors. Being there very early meant that we were the first to enter and we could experience the pitch black surroundings and the fluttering and squeaking sounds of the bats and swiftlets. We were happy to be wearing a helmet and a life jacket, mostly to protect us from any unpleasant souvenir coming from above - guano!

The limestone mountain above the subterranean river is known as the St. Paul Limestone Formation National Geological Monument. It was formed from the deposition of the remains of calcareous marine organisms approximately 39 million years ago, during the Oligocene period. The subterranean river inside Mount St. Paul and the karst tower of Tagabinet were carved after the St. Paul Limestone Formation was uplifted and gradually weathered by the action of surface water and groundwater.

Another important aspect which should not be overlooked is that what is currently accessible to tourists is just a small fraction of the whole subterranean river explored by speleologists (there are white graffiti present in the caves with some names). At present, the whole subterranean river and cave system has a total surveyed length of 21 kilometres, with only 8.2 kilometres that are navigable. Cave features such as stalactites, stalagmites, "curtains" and columns within the cave system continue to grow, being sustained by drip waters saturated with calcium carbonate. After your visit, if you have more time to kill, you can arrange with your motorised banka crew (some extra time for an extra fee) to stop you at the sandy beach just before the subterranean river beach for some swimming/snorkelling and/or ziplining too. To try to cover the mountain-to-the sea ecosystem element further, we stopped by car at a signposted hiking point to some more karstic formations and a view to Mount Cleopatra's Needle (similar environment but not part of the WHS), which is the mountain you will pass by on the way to the subterranean river. It offers a lush environment covered with forests full of birds and a worthwhile stopover if you rented a car.