A porbeagle shark Lamna nasus was found stranded at the sub-Antarctic Marion Island on 26 March 2014. The specimen, a sub-adult female, measuring 123 cm pre-caudal length, was photographically recorded and identified on the basis of its meristic traits. This observation is related to current information on the distribution of the species obtained from fisheries in the Southern Ocean and its feeding biology. The Onykia ingens squid specimen found in the specimen's stomach content matches the classification of porbeagle sharks as pelagic and demersal predators and adds to the cephalopod prey species list of the recently established Prince Edward Islands Marine Protected Area.