This research centres on student teachers’ practicum experiences to develop understandings of the importance of encounters between student teachers and learners in classrooms. In this international study, we investigate the interactions between student teachers and their mentoring teachers through data collected in three different teacher education settings, Australia, China and Sweden. Data consists of practicum narratives written by student teachers in response to these questions: What was the most memorable/critical moment in your practicum? (description) What did you learn from this moment? (reflection) How have your own background, previous life and professional experiences and university studies affected your becoming a teacher? (contextualization) Initial analysis of the narratives reveals that student teachers view their school, community and university mentors through different lenses in the different countries. Their perspectives also changed depending on the number of years they had been studying. Results indicate the critical nature of these encounters for the learning processes of student teachers and significantly mark the way they develop professionally. The role of reflective and focused professional dialogues will be discussed in terms of professional praxis, practice architectures (Kemmis & Grootenboer, 2008), teaching and learning ecologies (Kemmis, Edwards-Groves, Wilkinson and Hardy, in press) and practicum learning principles.