The White-bellied Heron is characterized by its overall dark gray plumage with a pale white belly and long, silvery or whitish plumes on the rear crown and lower neck. During the breeding season, it sports a grayish-white nape plume and elongated gray feathers on the chest with white centers. Its face is a greenish gray, and the bill is black with greenish hues near the base and tip, measuring 15.2 to 17.6 cm (6.0 to 6.9 in). The iris is yellow to ochre, and the legs and feet are a dull gray. Juvenile White-bellied Herons are browner on the back and have a paler bill and legs. In flight, the upperwing is uniformly dark gray, while the underwing shows white coverts that contrast with the dark gray flight feathers, and the rump appears pale gray.