The site contains unique biodiversity and heritage assets and a variety of landforms, habitats and wildlife including terrestrial, riverine, freshwater, brackish and coastal/marine ecosystems.

It was listed as a Wetland of International Importance because of its diversity of coastal and inland wetland types, support for populations of threatened species including a number of endangered turtles, maintenance of regional biodiversity, support for life-cycle functions such as turtle and waterbird breeding and refugia values, and its importance for providing important fish nursery and spawning habitats.

The site also has significant social and cultural values. It has a rich Indigenous, Macassan and European history. Indigenous people have lived on the Peninsula for over 40,000 years. It is considered that the Creation Ancestors first entered Australia via Malay Bay near the Cobourg Peninsula before travelling across the rest of the country creating people and places. The on-going role of the Traditional Owners (the Arrarrkbi) in the joint management of the site has helped to maintain its natural and cultural values.