This study focuses on mentoring as a vehicle for in-service science teachers' support in implementing innovative science teaching modules. Qualitative methods of analysis were used to examine mentors’ roles during the mentoring conversations and how these roles were altered. Our findings indicate that mentors tend to determine the focus of the mentoring conversations and to address the arisen issues using directive practices. In the same time they tend to shift their mentoring style towards more non-directive skills as the mentoring relationship progresses and when mentees have substantial background knowledge regarding the discussed topics. •Mentors tend to employ mainly directive practices and imperative roles.•Mentors use less directive skills over the course of time.•Mentors shift their style according to the mentees' expertise on each topic.•Mentors adapt their focus and style to the needs of their mentees.•Mentoring may support experienced in-service teachers apply educational innovations.