This article reports findings from a three-year qualitative study that explored the nature of translingual writing practices of the emergent multilingual youth who are ethnic Korean migrant children from Central Asia and Russia to South Korea. While settling into a new society, these emergent multilingual children tend to navigate and negotiate multiple languages, literacies, and identities. As a researcher and former teacher of Russian-speaking ethnic Korean migrant children in Korea, I became interested in examining how and why they engaged in translingual writing practices beyond school walls (referring to the capabilities and the processes of translingual language learners' appreciation, negotiation, and evaluation of multiple semiotic resources). Drawing upon 'translingualism' , this study gathered and analysed the data from multiple sources (i.e. observations, interviews, fieldnotes, and artefacts). The findings demonstrate the emergent multilingual youth's agentive engagement in translingual writing practices for differing purposes such as meaningful interaction, language development, and academic success. This study suggests that the dynamic and spontaneous use of multiple semiotic resources is the key to the emerging multilingual children's everyday communicative and literate lives as well as in the process of multilingual language development.