Educators' self-efficacy influences their practice and thus determines the quality of teaching in early childhood education and care (ECEC). This study analyzed educators' self-efficacy to teach physical education (PE) and the differences between pre-service and in-service early childhood educators. Early childhood educators (N = 381) completed a beliefs survey about their competencies to effectively teach PE in ECEC. Pre-service and in-service educators showed a discrepancy in their self-efficacy to teach PE, which can be attributed to their different conceptualizations of PE in ECEC. Additionally, self-efficacy was affected by work position (core practitioners vs. assistants), age of children taught (1-3 years old, 3-6 years old, or mixed groups of 1-6 years old), or how frequently educators read professional literature (never, rarely, or frequently). We propose pre- and in-service training in Slovenia to (1) promote an understanding of free play and skill-based practices in PE as existing on a continuum, (2) increase attention to educational approaches in PE employed in mixed-age groups, and (3) qualify educators for movement-skill demonstration.