We report a new locality record for the Mehuín Green Frog, Insuetophrynus acarpicus Barrio, 1970, a Critically Endangered species from southern Chile. The new locality is about 90 km southeast of the type locality and expands the known geographical distribution 40 km to the southeast. The new record confirms the presence of I. acarpicus south of the Lingue and Valdivia rivers. Our documentation demonstrates a discontinuous distribution of this frog in the Valdivian Coastal Range of Chile and intensifies the need to implement effective strategies for its conservation.