Spinebills are around 15 centimetres long. They are easily recognized by their long, thin, gently curved bills that they use for probing deep into flowers in search of nectar.
The plumage of males is more striking than females. Males have a black head that contrasts strongly with a white chin and throat where as the female has an olive-grey head but are otherwise similar to the.
Juveniles lack the distinct markings of adults being dark olive on the top of the head and back with a white chin and throat and a cinnamon chest and belly.