Paradise Cave is the most visited site in the park after Phong Nha Cave itself, and for good reason. The first kilometre of its 31-kilometre length is open to visitors, and that kilometre is extraordinary: a vast, cathedral-like passage with formations that took millions of years to build. Wooden boardwalks lead through the chamber, which is high enough in places that the ceiling is barely visible.
The entrance involves a 1.2-kilometre walk uphill from the car park (electric golf carts are available for those who prefer). It is accessible, busy during peak season, and still genuinely impressive. For a deeper experience, an 8-kilometre extension tour takes a small group beyond the tourist section into wilder, darker sections — this requires prior booking through local operators.