Eleutherodactylus humboldti has a triangular head and measures in snout-vent length. Its dorsal surfaces have small tubercles and are colored a brownish tan, whereas its ventral surfaces are translucent brownish tan with white tipped small tubercles on the belly and thighs. Its concealed surfaces on the posterior thigh and upper arm have an orange flash. The iris is split between a black lower half and a golden upper half.