Plankton was collected from more than 100 lentic and lotic habitats in Tasmania. Of the 131 rotifer taxa identified, 126 are first records for the island, and 9 are first records for Australia. Three new species, Aspelta tilba, sp. nov., Lepadella tyleri sp. nov., and Testudinella unicornuta sp. nov. are described and figured. Horaëlla brehmi, which has a disjunct distribution (equatorial regions and southeastern Australia), also occurs in Tasmanian waters. The morphology and development of this rare species are discussed. Geographical affinities of the Tasmanian assemblage are considered. There appears to be a significant tropical component in the Tasmanian Rotifera.