During work-integrated learning (WIL), student teachers usually practice what they have learned in theory under the apprenticeship of mentor lecturers and teachers. This experience might not adequately prepare them for the complexities of full-time teaching. To address this concern, 252 student teachers worked in small groups to identify challenges and to suggest effective ways of mediating cooperative learning during WIL in schools. The student teachers implemented what they had suggested and reflected on their learning experiences. Student teachers' field notes and discussions regarding their anxieties, uncertainties, beliefs, practices, orientations, and their reflection on the mediation of cooperative learning were analyzed. Findings show that the use of group discussion and reflection developed student teachers' teaching autonomy, which resulted in improved teaching. We argue that the combination of group-work and reflection is an effective way of developing student teacher autonomy and for preparing them for real-life classroom teaching.