The debriefing phase in mental health nursing simulation promotes a reflexive learning process with the opportunity to develop metacognitive and nontechnical skills. The aim of this quantitative study was to describe undergraduate nursing students' evaluation of their experience during the debriefing phase following high fidelity human simulation (HFHS). Data was collected using the "Debriefing Experience Scale" and analysed with descriptive and comparative tests. The debriefing phase was evaluated as very good. Background data and group size revealed few significant differences. Students with little clinical praxis evaluated having time to acknowledge feelings as important. Differences between groups revealed that groups should consist of up to eighteen students.