We examined the sources and role of coaching efficacy in coaching interest among female and male collegiate students majoring in sport sciences and physical education in Japan. We also examined the factor structure of a Japanese version of the coaching efficacy scale (CES-Japanese), and its measurement invariance between genders. This study included 908 college students. Results supported an exploratory structural equation modeling (ESEM) solution over confirmatory factor analysis for the CES-Japanese. Multiple-group ESEM demonstrated measurement invariance between genders. A path analysis adding sources of coaching efficacy and coaching interests showed that coaching interest was positively related to motivation efficacy among female students and to teaching technique and character building efficacy among male students. Relationships between the sources and coaching efficacy differed between genders. Our findings provide initial validity evidence regarding the CES-Japanese and advance our understanding of the sources and influence of coaching efficacy among potential coaches in development.