Transnational doctoral students, who travel across geographic, social, ideological, and linguistic boundaries, embark on a new journey in academic and professional spaces. Additionally, rapid development in communication technologies and the increasing participation of transnational doctoral students in digital spaces have attracted growing research interest in online communities for navigating transnational life. However, limited research has examined how transnational students build supportive learning communities and negotiate translingual identities while fostering savviness in academia in digital contexts. To fill this gap, this study adopts a digital ethnographic and discourse analysis approach to examine the online interactions of transnational Chinese doctoral students within a WeChat group in the United States. Informed by the conceptual framework of communities of practice and translanguaging, this study addresses two research questions: (1) How do transnational doctoral students engage in translanguaging practices to build a support network in the WeChat group? (2) How do their interactions in the online space reveal the translingual identities of transnational doctoral students? Through participant observation of group chat records, the preliminary findings show transnational doctoral students deploy linguistic and non-linguistic semiotic resources to navigate challenges and tensions in multicultural contexts. This study offers social, cultural, educational, and technological insights and nuances for better supporting transnational students in the ebb and flow of global mobility.