The Eastern Spinebill is most easily recognised by its very long, fine, down-curved beak and energetic flight, during which its white outer tail feathers are prominent. Males have a grey-black crown which extends in a black line on either site of the breast. The breast and throat are white, with a rufous patch in the centre of the throat. The wings and lower back are dark grey and the underparts and upper back are buff. Females are similar to males but have less distinct markings.