This study aimed to explore the nature of changes in pre-service science teachers’ (PSTs’) self-efficacy beliefs toward science teaching through a mixed-methods approach. The findings revealed that microteaching sessions provided pre-service teachers experiences in a controlled and supportive environment. The microteaching process also provided vicarious experiences to the PSTs through observation of teaching performance of teammates and other participants. The a collaborative peer microteaching (Cope-M) process created a practice of discussion-based and supportive teaching to shift the PSTs’ teaching practice to a more robust understanding. Furthermore, the findings suggested that the level of self-efficacy beliefs toward science teaching were positively affected by the Cope-M and were affected slightly negatively after early field experiences.