13–16 cm (5–6 in) long, the male Eastern Spinebill has a long thin downcurved black bill with a black head, white throat with a reddish patch and red iris. It has a brownish-red nape, a grey brown back and pale cinnamon underparts. The dark tail is tipped with white laterally. Females and juveniles are smaller and duller. The call is a rapid piping.