Although previous studies using single research methods have examined the impact of simulated interprofessional education (SIPE), a comprehensive understanding of its effects remains limited. Additionally, many studies lack a theoretical framework to guide teaching design, reducing methodological rigor. This study aimed to investigate the effects of a 3P theory–based SIPE model on the “Clinical Critical Thinking Training” course using a convergent mixed-methods approach, providing evidence to inform future educational strategies. A convergent mixed-methods design was employed, combining quantitative surveys and semi-structured interviews. Data were collected between September 2021 and July 2022. Using cluster sampling, 60 full-time nursing students from a Chinese university were randomly assigned to a control group (n = 36) or an experimental group (n = 24). To form interprofessional teams in the experimental group, six students from clinical medicine and six from pharmacy volunteered to participate. Both groups completed the “Clinical Critical Thinking Training” course, with the control group receiving traditional simulation instruction and the experimental group participating in SIPE. Quantitative outcomes were measured pre- and post-course using the California Critical Thinking Disposition Inventory (CCTDI) and the Assessment of Interprofessional Team Collaboration in Student Learning Scale (AITCS-II Student). Descriptive statistics and the Mann–Whitney U test were applied to compare critical thinking and interprofessional collaboration skills between groups. Qualitative data from semi-structured interviews were analyzed thematically to explore students’ development of interprofessional competencies and learning experiences. Both groups showed improvements in critical thinking and interprofessional collaboration after the course; however, the experimental group demonstrated significantly greater gains compared to the control group (p < 0.05). Three main themes emerged from the qualitative analysis: clarifying team roles, enhancing team efficiency, and optimizing the overall learning experience. The 3P theory–based SIPE model effectively enhanced nursing students’ critical thinking, teamwork, and interprofessional competencies, suggesting its value as a structured approach for interprofessional education.
