The external morphology and anatomy of the Antarctic nudibranchsTritonia voraxOdhner, 1926, andTritonia antarcticaPfeffer in Martens&Pfeffer, 1886, is redescribed in detail and compared with other nominal tritoniids from the Antarctic and Subantarctic waters.Tritonia appendiculataEliot, 1905,T. challengerianaEliot, 1907a, non Bergh, 1884,T. chalkngerianaOdhner 1926, non Bergh, 1884, andMarionia cmullataVicente&Arnaud 1974, non (Couthouy, in Gould 1852), are shown to be synonymous withT. antarctica.OnlyTritonia antarcticais a true High Antarctic species, with a distribution around the continental shelf, Antarctic Peninsula and South Georgia.T. voraxis confined to South Georgia and Subantarctic waters.