Thuidium delicatulum (Hedw.) Schimp. is recorded from Marion Island in the Prince Edward Islands Archipelago in the Subantarctic. This is the first report of the genus Thuidium Schimp. from the subpolar region of the Southern Hemisphere and establishes Th. delicatulum as a bipolar species with intermediate localities in the tropical zone, in Central America and the northern and central Andes in South America. The Marion Island plants are described and their ecology and distribution on the island discussed. The world distribution of Th. delicatulum is reviewed and some speculations presented regarding the origin of the Marion Island population.