The Puerto Princesa Subterranean River National Park (PPSRNP) is one of the most important biodiversity conservation areas of the Philippines. The river also called Puerto Princesa Underground River. It features a spectacular limestone or karst landscape that contains an 8.2 km long underground river. A distinguishing feature of the river is that it flows directly into the sea, and the lower half portion of the river is brackish and subject to tidal influence. The area also represents significant habitat for biodiversity conservation. It contains a full mountain to the sea ecosystem and protects forests, which are among the most significant in Asia.

The PPPSRNP is designated a core area for the Palawan Biosphere Reserve under the Man and Biosphere Program. In recognition of its globally significant natural properties, it was inscribed to the United Nations Educational, Scientific and Cultural Organization’s of (UNESCO) List of Natural World Heritage Sites. Inscription to the list confirms the exceptional and universal value of the Site that deserves to be protected for the benefit of all humanity.

The PPSRNP is managed by the City Government of Puerto Princesa based on a program centered on environmental conservation and sustainable development. It has the distinction of being the first national park devolved and successfully managed by a Local Government Unit. It has been cited as an example of best practices for biodiversity conservation and sustainable tourism in the Philippines.

The Puerto Princesa Underground River is reputed to be the longest navigable underground river in the World. It is one of the few such rivers which the public can easily experience and appreciate. It is the official entry of the Philippines and is 1 of the 28 finalists to the Search for the New 7 Wonders of Nature.

It is a source of pride and a key element in the identity of the people of Puerto Princesa in particular, and of the Philippines as a whole