Wadbilliga has many impressive examples of open forest, woodland, heath, swamp, bogs and numerous pockets of rainforest. There are some rare species of eucalypt and acacia that do not occur anywhere else. In the Wadbilliga Valley, yellow box and forest red gum can be seen, while on the ridge tops tower large stands of silvertop ash with snow gums at high altitudes. The Wadbilliga Plateau also has dwarf she-oaks and rare stunted mallee eucalypts.

The surrounding area has a variety of artefacts, structures and features that hark back to gold and silver mining eras, as well as the early forestry history of the local area. Today, visitors can still view various mining remains that are evidence of once arduous searches for gold and other precious materials.

Due to the rugged and isolated nature of the park, animal populations here have remained relatively undisturbed. Many of the park's animals are large marsupials such as swamp wallabies, eastern grey kangaroos and wombats. There are also possums, platypuses and echidnas and one of the biggest greater glider populations in all of Australia. The birdlife is varied too, with over 120 native species. Lyrebirds are common as are many colourful and tuneful bush birds.

The Yuin people consider Wadbilliga National Park a sacred place and many sites in the park are strongly associated with Dreamtime stories. The dissected, rugged escarpment contains a network of bridle tracks that follow both high country and river courses, which Aboriginal people originally used. The bridle tracks are also the most tangible historical link with the first Europeans in the area and were used for transporting produce and moving stock from one location to another. The park is abundant in traditional foods and medicines.