Lymnaea tomentosa is a species of freshwater snail, an aquatic gastropod mollusc in the family Lymnaeidae. This species lives in New Zealand. These snails are found in both the North and South Islands and on aquatic plants in swamps, ponds, and quiet waters. In Australia (in particular South-East New South Wales), this species was reported to serve as one of the most important intermediate hosts for liver fluke (Fasciola hepatica).