The Great Egret is a large bird with all-white plumage that can reach one meter in height, weigh up to 950 grams (2.1 lb) and a wingspan of 165 to 215 cm (65 to 85 in). It is thus only slightly smaller than the Great Blue or Grey Heron (A. cinerea). Apart from size, the Great Egret can be distinguished from other white egrets by its yellow bill and black legs and feet, though the bill may become darker and the lower legs lighter in the breeding season. In breeding plumage, delicate ornamental feathers are borne on the back. Males and females are identical in appearance; juveniles look like non-breeding adults. It is a common species, usually easily seen.
It has a slow flight, with its neck retracted. This is characteristic of herons and bitterns, and distinguishes them from storks, cranes, ibises, and spoonbills, which extend their necks in flight.
The Great Egret is not normally a vocal bird; at breeding colonies, however, it often gives a loud croaking cuk cuk cuk.