This article presents ethnographic data of US Mexican-indigenous heritage children's transnational experiences during return visits to Mexico. US-born children and youth's acquisition of transnational diasporic community knowledge, in this article, is studied as a form of "smartness." Diasporic community knowledge is defined as the "saberes" (knowings) and "smartness" developed in relation with "familia" (family) and community life that originate, in this case, in the "pueblo" of San Miguel Nocutzepo, and that span the geo-physical and geo-political spaces of migration to and from the US. This study finds that these return visit experiences and the "saberes"/smartness acquired and developed through them were valuable to families and children because they socialize US Mexican-indigenous heritage children and youth in different knowledge systems, and allow them a smartness that is ancestral and that encourages mature participation in diasporic family and community life across transnational social fields.