Clinical workplaces offer postgraduate trainees a wealth of opportunities to learn from experience. To promote deliberate and meaningful learning self-regulated learning skills are foundational. We explored trainees’ learning activities related to patient encounters to better understand what aspects of self-regulated learning contribute to trainees’ development, and to explore supervisor’s role herein. We conducted a qualitative non-participant observational study in seven general practices. During two days we observed trainee’s patient encounters, daily debriefing sessions and educational meetings between trainee and supervisor and interviewed them separately afterwards. Data collection and analysis were iterative and inspired by a phenomenological approach. To organise data we used networks, time-ordered matrices and codebooks. Self-regulated learning supported trainees to increasingly perform independently. They engaged in self-regulated learning before, during and after encounters. Trainees’ activities depended on the type of medical problem presented and on patient, trainee and supervisor characteristics. Trainees used their sense of confidence to decide if they could manage the encounter alone or if they should consult their supervisor. They deliberately used feedback on their performance and engaged in reflection. Supervisors appeared vital in trainees’ learning by reassuring trainees, discussing experience, knowledge and professional issues, identifying possible unawareness of incompetence, assessing performance and securing patient safety. Self-confidence, reflection and feedback, and support from the supervisor are important aspects of self-regulated learning in practice. The results reflect how self-regulated learning and self-entrustment promote trainees’ increased participation in the workplace. Securing organized moments of interaction with supervisors is beneficial to trainees’ self-regulated learning.