This study was designed to determine the impact of 12-week student teaching semesters on student teachers' self-efficacy and outcome expectancy beliefs in teaching physical education classes. A pre-post design was used to examine changes in beliefs of 107 physical education student teachers. Self-efficacy (instructional strategies, class management, and student engagement) and outcome expectancy beliefs were measured by validated questionnaires. Data collection spanned over a 2-year period. The pretest was completed at the third week of the student teaching semesters, and the posttest was conducted at the end of the semesters. The results suggested that all student teachers' self-efficacy and outcome expectancy beliefs increased significantly (p < 0.05) over time. Therefore, we concluded that the student teaching experiences had a positive effect on physical education student teachers' beliefs during this crucial early stage of their prospective teaching careers.