This multi-sited ethnographic case study examines how transnationalism shapes the everyday lives of young immigrant children, particularly their literacies, identities, and learning. This study involved three second-generation Korean immigrant children whose lives encompass multiple languages, cultures, and countries through close connections with their parental homelands. Informed by a transnationalism framework and sociocultural perspective on literacy, I focused on three specific questions: How do second-generation immigrant children engage with language and literacy in and across various spaces? What transnational funds of knowledge do they build as they move across contexts? How do they position themselves and represent their identities? I employed a multi-sited ethnographic stance and collected data for one year in two locations: North Carolina, United States, and Seoul, South Korea. The data collected include participant observations, fieldnotes, parent questionnaires and interviews, child-centered interview activities, artifacts, documents, photographs, and a reflective journal. Findings from the research indicated that second-generation immigrant children play crucial roles in building, maintaining, and extending transnational networks. As these children moved across geographical boundaries, they flexibly drew on multiple languages, linguistic features, and modes. As active agents, they engaged in the circulation of care by circulating love, support, and educational resources with family members across national borders. The children also mobilized their transnational funds of knowledge beyond local-global contexts through playful engagements that I refer to as transcultural play. Finally, the children presented complex and evolving transnational ways of belonging, which demonstrated that active participation in transnational practices does not necessarily lead to strong identification with the parents’ home culture. This study provides a more comprehensive and nuanced picture of young immigrant children living in a transnational and transcultural world and challenges previous claims that second-generation immigrants lose meaningful connections with their parental homelands. By demonstrating the flexibility and mobility of young immigrant children’s literacies, identities, and learning, I provide theoretical, methodological, and pedagogical insights that are essential for researchers and educators interested in cultivating a transnational curriculum and honoring young immigrant children’s mobile experiences.