The island is a limestone cover of an ancient submerged volcano, with eroded terraces and an interior plateau.

The Cocos Islands are also built on submerged seamounts, but the surface is limited to a low-lying coral atoll.

The characteristic tree species are Planchonella nitida, Syzygium nervosum, Tristiropsis acutangula, Inocarpus fagifer, and Hernandia ovigera.

Undergrowth that exists is typically the vulnerable Lister's palm (Arenga listeri) and Pandanus elatus .

[1] Over 100 million red crabs (Gecarcoidea natalis) are estimated to live in the woods; they keep most of the forest floor clear of fallen leaves and other litter.