The 1989 Convention on the Rights of the Child reflects the role and status of children in society as being competent and capable participants on matters that affect them. The Convention is foundational in understanding children's rights to participate in all aspects of everyday life, including in research in which children are participants. This article explores children's rights to participate within a research study that investigated their play activities in preschool. This study was conducted with 46 children aged 3-5 years in two preschool settings in Iceland. We make connections across a range of research practices involving the children, including ethical matters that arose during the research process, and data collection methods that supported children in communicating their perspectives about their preschool activities using a video-stimulated accounts method. The findings show that the children communicated and negotiated their assent or dissent in various ways and at different times in the research process. The study recognises the delicate balance between the researcher's agenda and the children's rights, and offers suggestions for those considering undertaking research with young children.