During a preliminary survey of the non-marine diatom flora of the volcanic island, Île Amsterdam (southern Indian Ocean), five species belonging to the genus Eunotia have been found. Apart from Eunotia paludosa var. paludosa and E. muscicola var. muscicola, three appear to be new to science and are described as E. pugilistica Van de Vijver sp. nov., E. lecohui Van de Vijver sp. nov. and E. cocquytiae sp. nov. All species are fully investigated using both LM and SEM techniques. The new taxa are compared with similar species. Notes on their ecology and associated diatom communities are added. Finally, the biogeographical position of Île Amsterdam based on the genus Eunotia is briefly discussed.