Nine species of water mites (Acari, Hydrachnidia) were collected in 2017 from two rivers in Sri Lanka. One genus, i.e. Srilankurus, and four species, i.e Atractides biesiadkai, Axonopsis srilankensis, Brachypodopsis mirkae and Srilankurus biprojectus are described as new for science; Monatractides pinapalpis (Cook, 1967), a species so far known from India only, is reported as new for the fauna of Sri Lanka. The number of water mites known from Sri Lanka now tallies 60 species.