Larvae of two heptageniid mayflies, Iron martinus Braasch and Sold${acute}$n and Iron longitibius sp. n., are described from Vietnam. The larva of I. martinus is distinguished by the paired spines on the abdominal segments 1-9; the larva of I. longitibius sp. n. is distinguished by the relatively long foretibiae. Their descriptions, diagnoses, line drawings of key characters, material examined, distributions, and habitat and biology data are provided.