This paper examines the role of dialogue for learning about and enacting teaching within critical mentoring conversations between pre-service teachers (PSTs) and classroom teacher mentors. The paper draws on a broader two-year intervention study, conducted in a teacher education faculty in rural Australia. The empirical study centred on the development of quality classroom interactions and dialogic pedagogies of PSTs as they practice learning to teach in authentic school-based situations; these are issues of practical concern for education globally. The paper presents an in-depth analysis of a single case study of mentoring conversations and follow-up interviews with PSTs and their teacher mentor. The transcript analysis--presented as talk-in-interaction--enabled the close and continual examination of participants? practices and afforded the opportunity to elicit the intricacies of social actions to elicit themes about: i) the conduct of mentoring conversations, ii) how mentoring unfolded discursively as sequences of interaction, and iii) how these produced displays of learning among PSTs. Results reveal firstly "how" mentoring conversations unfold structurally in activity time space and how these were learning conversations which were pedagogical, collaborative, analytic, dialogic and evidence-based. Critical mentoring conversations enabled PSTs to build a strong practice-theory base around the classroom exchanges experienced, observed and critiqued.