There is a need to reflect on both the processes and outcomes of the range of approaches aimed at promoting children's engagement in research, with the specific intent of listening to children's voices. This article considers some of the ethical tensions we have experienced when engaging children in research about their prior-to-school and school environments and their perspectives of the transitions between these environments. Examples from projects conducted in Iceland and Australia are drawn upon to illustrate these tensions and, to reflect on the strategies and questions we have developed to guide our engagement with children. This article raises issues rather than offering simple solutions. We suggest that there are a number of contextual and relational variables that guide our research interactions, and no "one best solution" applicable to all contexts. Our aim in sharing these tensions is to stimulate further debate and discussions around children's participation in research.