The potential of synchronous technology-mediated oral interaction for second language (L2) acquisition by young learners interests researchers and classroom teachers alike. Research highlights the utility of live telecollaborative exchange for motivating learners, but also underlines the challenges teachers face in supporting young beginners in interaction tasks. However, few studies focus on actual learning opportunities created in telecollaborative task-based language teaching (TBLT) and on the role of teachers in creating such opportunities. This paper presents two case studies on synchronous telecollaboration in primary schools (7-10 year olds, A1 CEFR level). Interaction data from small-group telecollaborative interactions is examined using multimodal (inter)action analysis (MIA, Norris, 2019) to investigate how teachers’ choices with respect to task implementation affect opportunities for learner autonomy, the outcome of particular tasks, and learners’ L2 usage. Analysis highlights how co-verbal actions are used to manage different interactional spaces and reveal learners’ active roles, and how teacher presence/absence can affect task outcome and influence opportunities for either focus on form or spontaneous L2 production. Our discussion shows that synchronous interaction can drive language learning with young learners, not only motivation and participation, and focuses on implications for further research combining MIA with TBLT.