Radfordia (Microtimyobia) mites infesting arvicoline voles in Japan comprise three new subspecies of Radfordia (M.) lemnina (Koch, 1841). These new subspecies are defined on the basis of the form of the male genitalia, the shape of the anterior gnathosomal setae, and the chaetotaxy of the female tritonymph. Radfordia (M.) lemnina hata ssp. n. is a parasite of Microtus montebelli (Milne-Edwards, 1872). Radfordia (M.) lemnina mikado ssp. n. infests only Clethrionomys rutilus mikado Thomas, 1905 in Hokkaido, and it differs from Radfordia (M.) lemnina rutila Fain and Lukoshus, 1977 parasitizing Clethrionomys rutilus (Pallas, 1979) in Europe. Radfordia (M.) lemnina japonica ssp. n. is found widely on the other Clethrionomys and Eothenomys voles in Japan. Among these host voles, Clethrionomys rufocanus bedfordiae Thomas, 1905 is designated as the type host of this new subspecies. Immature stages of the three new subspecies are described and illustrated. Radfordia mites parasitic on Eothenomys voles in Taiwan and Japan are much more different from each other than would be expected on the basis of the current systematics of the Arvicolinae proposed by Japanese mammalogists.