Internationally, teacher education usually involves close school-university cooperation. In Norway, such collaboration includes enabling student teachers to develop into researching teachers. In this article, our interest lies in how the Change Laboratory (CL), a form of participatory workshop, can lay the foundation for three-way collaboration between student teachers, teacher educators, and practice teachers, in terms of resolving practice issues and facilitating student teachers' research planning. The study, contextualised within cultural historical activity theory (CHAT), sought to better understand student teachers' experiences and learning gleaned from collaboration in the CL. Eight student teachers participated in the research, which was carried out over a four-year teacher education research and development project involving one university and one primary school. During this time, the student teachers met in the CL with the teacher educators from the university, and the practice teachers, who were working as mentors in the training schools. The data collected, comprising presentations and dialogues from the CL sessions, were analysed qualitatively. According to the analysis, the student teachers thought that their CL experiences had supported them along the trajectory of becoming reflective, professionally oriented practitioners. They felt that, through participatory meetings with the teacher educators and practice teachers, they had developed in-depth subject knowledge; learned to collaborate; learned about school development; and learned how to be well prepared for the profession they were entering. In addition, they considered whether the project could be expanded to the entire teacher education system. The findings draw broader attention to the role of participatory meeting places in creating a community of trust, and their potential to support teachers' learning at crucial stages of their professional journeys, from early career phases and beyond. [ABSTRACT FROM AUTHOR]