Understanding the mechanisms of genetic diversity and how they lead to phenotype diversity remain a fundamental question in evolutionary biology. Land snails are potentially excellent systems to investigate phenotypic evolution, because phenotypic traits tend to show high variability, as a result of low mobility and strict habitat dependences. Extreme shell shape variation is recognized in the bradybaenid land snails of Northeast Asia. Phenotypic traits of this group have been much diversified in inter- and intra-species levels, and usually indicate sympatric distribution pattern. In the previous study, molecular phylogenetic relationships were inferred from the bradybaenid land snails (Ainohelix, Ezohelix, Karaftohelix, Paraegista) in Hokkaido Island, suggesting that these genera were genetically fairly close to each other. In the present study, we focused on the inter- and intra-specific relationships among the Northeast Asian bradybaenid land snails including species of both Far East Russia and Hokkaido. On the basis of the inferred phylogeny, we documented phenotypic diversity patterns and historical biogeography, and discuss the mechanisms of patterns of radiation observed in these species.