The concept of ‘transpositioning’ is an emerging notion in the field of Applied Linguistics, influenced by positioning theory and liquid modernity. Transpositioning involves individuals breaking away from their predefined roles and adopting different perspectives through translanguaging. However, there is currently a lack of research exploring how multilingual classroom teachers can transcend their positions using translanguaging to achieve their specific communication goals in multilingual classrooms. This study is the first study that investigates how an English-Medium-Instruction teacher undergoes transpositioning by adopting different positionings to construct an imaginary scenario and engaging in co-learning with students. The study employs Multimodal Conversation Analysis to analyse the classroom interaction data, and the findings are triangulated with video-stimulated-recall-interview data, which is analysed using Interpretative Phenomenological Analysis. The paper argues that transpositioning is a fundamental aspect of the teacher’s classroom translanguaging competence. This competence involves not only the strategic utilization of multilingual and multimodal resources to construct new knowledge and achieve specific pedagogical goals, but also requires the teacher to selectively draw from his repertoire and modify his identity positions in response to the evolving dynamics of classroom interaction.