This paper reports on the reflective practice of a group of nine secondary mathematics pre-service teachers. The pre-service teachers participated in a year-long, school-based professional experience program which focussed on observing, co-teaching and reflecting on a series of problem-solving lessons in two junior secondary school mathematics classrooms. The study used a mixed methods approach to consider the impact of shared pedagogical conversations on pre-service teachers' written reflections. It also examined whether there were differences in the focus of reflections depending on whether the lesson was taught by an experienced mathematics teacher, or taught by a pair of their peers, or co-taught by themselves with a peer. Results suggest that after participants have observed lessons taught by an experienced teacher and reflected collaboratively on those lessons, they continue to reflect on lessons taught by their peers and on their own lessons when co-teaching, rather than just describe or evaluate them. However, their written reflections across all contexts continued to focus primarily on teacher actions and classroom management rather than on student learning.