The coot is 36–38 cm in length with a wing-span of 70–80 cm; males weigh around 890 grams and females 750 grams). It is largely black except for the white bill and frontal shield. As a swimming species, the coot has partial webbing on its long strong toes.

It is an aggressive species, and strongly territorial during the breeding season, and both parents are involved in territorial defence. During the non-breeding season they may form large flocks.

It is reluctant to fly and when taking off runs across the water surface with much splashing. The nest is a bulky structure that either floats on the water or is built in shallow water on a low or barely submerged stump or log.