Introduction/Background Debriefing facilitates participants learning from the simulated experiences through reflection and feedback. The value of debriefing post scenario in simulation-based education (SBE) has been well documented. For example, a review by McGaghie et al1 identifies feedback (including debriefing) as the most important feature of SBE.1 There are many different models and approaches to facilitate debriefing in SBE within healthcare, building on research, experiences and practical application. However, there is little evidence supporting one approach over another. It is likely that several variables are important such as what is taught, the level of learners, their experience and not least the educator. 2,3 Though the literature describes what constitutes effective debriefing, there are discrepancies as to what is actually being practiced.4 There is limited information as to how experts or experienced debriefers practice.4 This national study explores the practice of expert debriefers, who work within full-scale, high-stakes immersive SBE environments. Methods Individual semi-structured interviews were conducted with experts in debriefing after immersive simulation based education. Respondents were nominated by peers through purposive sampling across Australian states. Interviews were audio recorded and transcribed for thematic analysis with NVivo9. Three researchers working independently each inductively coded between three and five transcripts and jointly developed a high level coding framework, used to guide a deductive interpretive thematic analysis of all interviews. Triangulation through independent analysis continued throughout the thematic analysis process. Ethical approval was obtained for the study and all participants signed a consent form. Results A total of 24 interviews of 45-95 minutes were transcribed. Participants were from all states of Australia. The majority of participants were located in larger cities such as Melbourne, Sydney, Brisbane, Perth and Adelaide from 20 different workplaces and centres, 6 different disciplines and 14 sub-disciplines. The participants had between 4 and 23 years of experience with debriefing in SBE, with an average of 9.7 years of experience. The three high order categories are: features of expert practice, the development of expertise and the influence of context upon debriefing practice. Analysis is indicating that dominant practice features include: debriefing models used, video assisted debriefing, briefing and continues professional development. Most participants used a blended approach to debriefing combining different models to fit the need of the learners and the contexts of the simulated scenario and the debriefing. Key success factors identified by several participants were: the importance of showing genuine interest, being honest and continuing to strive for being better by continues professional development. Influences on debriefing practice included a range of peer interactions such as: peer feedback, observation of other debriefers, formalized courses in debriefing and conference workshop participation. Conclusion This study looks at the self-reported practices of expert debriefers. The purposive sampling covered a large range of disciplines and no new themes (saturation) were introduced within the final interview set. While there were many convergent features of expert practice and development, there were also context-dependent divergences. The need for peer interaction to develop and sustain expertise was marked. This study contributes to the research on debriefing in SBE by bringing evidence to the use of a highly contextualized approach to debriefing to fit the need of the learners. The interviewed expert debriefers do not use a single model for practice but have a blended approach to debriefing with genuine interest and honesty as the main drivers.