Discover the cave that gives the entire national park its name: Phong Nha Cave. This remarkable cave is unique among the main attractions as it's accessed primarily by boat. Your journey begins with a scenic boat trip along the Son River, passing traditional villages and limestone cliffs, before the boat motors are cut, and you are gently rowed directly into the cave's entrance, entering a subterranean world. It's one of the key components of the Phong Nha-Ke Bang UNESCO World Heritage site.

Inside, Phong Nha Cave is renowned for having one of the world's longest underground rivers. The boat glides silently through vast, cathedral-like chambers adorned with impressive stalactites and stalagmites, subtly illuminated to reveal their shapes. After cruising along the underground river for some distance, visitors typically disembark onto sandy banks inside the cave to explore a section of higher, dry chambers on foot, marvelling at the sheer scale and diverse formations before returning via boat.

Visiting Phong Nha Cave offers a classic and relatively accessible cave experience, suitable for most visitors. The combination of the serene river journey and the exploration of the vast underground chambers makes it a popular first cave to visit in the area. Remember to appreciate the silence once the boat engine cuts off – it adds to the mystical atmosphere of floating through this ancient subterranean wonder.