The article explores a professional learning programme, a research circle, in which preschool teachers and researchers collaborate on content relating to sustainable development, science and technology. It investigates how collaborations between preschool teachers and researchers can contribute to professional learning and preschool development. The research focuses on experiences of participation in research circles and makes use of Participatory Action Research (PAR). The data consists of twelve preschool teachers’ written documentation as preparation for seminars in the research circle and semi-structured interviews with eight preschool teachers. The analysis explores three bodies of social and educational change: individuals, teams and organisations. The overall conclusion is that participation in a research circle support preschool teachers to become more aware of their own practices, address issues and challenges and make improvements in a collaborative and reflective way, it is a useful tool for preschool teachers’ professional learning and preschool development.