Purpose: This study examines the effects of clinical nursing simulation education program based on problem-based learning (S-PBL) on clinical reasoning, confidence in handover reports, confidence in nursing performance, and simulation effectiveness in nursing students. Method: We used a one-group pretest-posttest design. The participants were 4th-year university nursing students who had taken a core clinical nursing practice, and 90 students participated in the S-PBL program. Data were collected before and after the S-PBL program and analyzed using descriptive statistics and paired t-tests. Results: The S-PBL program significantly increased clinical reasoning, confidence in handover reports, and confidence in nursing performance. More than 90% of students were satisfied with the education program and the simulation education effectiveness was 2.54 on a 3-point Likert scale. Conclusion: The S-PBL program could be useful in clinical nursing education for nursing students seeking to become clinical nurses. It is necessary to develop various S-PBL programs and apply them to the curriculum.