A highlight of our trip! - This tour was definitely a highlight of our time in Vietnam. The cave was truly amazing and it was very cool to see the array of stalactites and stalagmites. We were picked up from our Homestay and taken to a hotel where we were given rubber sandals to wear for the tour. They only catered up to a size 43 so some of the guys had to squeeze their feet in! Note: you want these to fit snugly. We were told to put everything we wanted to take inside the cave into a wet bag (some were provided but if you have your own, I would recommend bringing it). We wore our bathers under our clothes because we knew the tour involved a swim and put towels and phones into the wet bag. If you have one of those waterproof phone cases with a lanyard, bring it. They sell them on the bus to the cave if you want to buy (they were not expensive). Wear clothes you feel comfortable getting wet and dirty! We arrived at the river leading into the cave and were given our lifejackets and helmets (with head torch attached) and headed into our inflatable kayaks. Off we went into the cave which was lit for about 1.5km. We continued to kayak for another 1.5km in the darkness with our torches on. The guide brings plenty of spare batteries and lots of water. We then left the kayaks and began our hike/rock climb another 1.5km into the cave. At this point the air was pretty thick and humid and it was quite hot inside the cave. Very sweaty! The hike was challenging and at some points quite scary. There were slippery rocks, steep faces and large drop-offs either side. Everyone took their time and made it through safely. The cave was never claustrophobic - it was very wide at all times. It was mainly the humidity and low oxygen that proved challenging, personally. We took frequent stops and water breaks and our guide told us lots about the cave. We reached the end of the hike and came to a small beach where we had the option of going for a swim before turning around back the way we came. I would recommend the swim, it was very refreshing and there were lots of sandbanks to stand on. After returning to the kayaks and paddling back towards the cave entrance, we stopped off at another beach and ate the lunch provided. We then walked about 700m to see the cave inscriptions and learnt about the Cham people. After finishing with a lovely easy walk though Fairy Cave (which is just inside the mouth of Phong Nha Cave), we kayaked back across the river to the bus and we’re dropped back at the homestay. Overall, would absolutely recommend the tour if you have a good baseline fitness and a good sense of adventure. We didn’t quite know what we were getting into so hopefully this review helps!