You'll find littoral (or coastal) rainforest in the park's gullies and in sheltered spots behind the huge sand dunes. This type of plant community has been much reduced by development and agriculture elsewhere along the coast. It survives in small remnants, mainly in national parks like Hat Head.
In the park's higher areas, heathland is replaced by eucalypt woodlands. This, in turn, is replaced by eucalypt forests and rainforests in areas of moister, richer soil.
The park has some of the largest 'live' sand dunes in New South Wales. The dunes provide a buffer from the ocean, protecting the land from salty winds and waves. They are growing and moving inland.
You'll find heath shrubland growing in the dry, sandy areas around the dunes. It's dominated by banksias. In spring, the heath shrubland bursts into a kaleidoscope of wild flowers, attracting many birds.
Another type of community, sedgeland, is found in areas of moist, sandy soil. Sedgeland has many varieties of tall, slim and spiky sedges, rushes and lilies.
There are extensive wetlands in Hat Head National Park, running parallel to the sweeping beaches. These wetlands are being overrun by the park's huge moving dunes.
You'll find areas of swamp forest as you explore the park. Trees such as paperbarks (melaleucas) and swamp mahoganies grow here. They have evolved to live in permanantly waterlogged areas.