Background Simulation has proven valuable in nursing communication training, but there are limited studies comparing the effectiveness of different training methods, especially in the area of adverse event disclosure (AED) training. Therefore, this study aimed to examine the impact of two training methods, peer role-play (PRP) and simulated patients (SP) on the self-efficacy and performance of nursing students in AED in a simulated environment. Methods Forty-four nursing students participated. Students' self-efficacy toward AED was assessed using the pre/post-test method. Also, students' performance was evaluated after the simulation encounter. Results It showed a significant difference in self-efficacy between the groups. However, no significant difference emerged between the groups in performance. Conclusion This study provides a basis for comparison of these two methods in patient communication training. Educators should consider their resources and expected learning outcomes in designing the emotionally draining adverse event disclosure training.