Several ecological and evolutionary principles have been developed from observations or experiments realized in insular systems. This is especially true for ants that have been at the core of the development for some of the main macroecological theories. Determining the main factors that determine modern community diversity and composition is still a central goal of macroecology. In particular, what is the importance of historical versus environmental factors in shaping modern communities remains an important question. Here we used data from a newly developed global database on ant distribution to test the factors influencing community composition in Eastern Asia; with a specific focus on Japan and surrounding islands, summarizing information for 70 continental regions and 118 islands. Our results show that ant composition similarity between regions is mainly explained by geographic distance, temperature and past land connectivity during the Pleistocene. In contrast, precipitation, elevation range and current connectivity were not significant predictors. In conclusion, our results highlight the importance to consider current environmental conditions as well as historical biogeography to understand the formation and composition of communities.