Preschool teachers' science-specific competences have been shown to influence their science instruction, which in turn appear directly related to the development of children's science competences. Initial teacher education and in-service professional development may include learning opportunities to acquire science-specific competences necessary for teaching science in preschool. Knowledge about the effects of learning opportunities in initial teacher education and in-service professional development on preschool teachers' science-specific competences is limited but highly relevant for research, policy and practice. This paper examines the effects of learning opportunities in preschool teachers' initial teacher education and in-service professional development on their science-specific professional knowledge and motivation regarding early science education. Controlling for preschool teachers' socio-demographic and educational background and their learning opportunities in their initial teacher education, regression analysis revealed significant positive relations between in-service professional development courses and their self-efficacy beliefs, enthusiasm and science-specific content knowledge. With regard to science courses in initial teacher education, controlling for preschool teachers' socio-demographic and educational background and the number of professional development courses taken, we found significant positive relations between the courses in initial teacher education and their science-specific pedagogical content knowledge and self-efficacy beliefs. These results indicate that the provided learning opportunities provided could promote preschool teachers' competences. However, due to the heterogeneity in the learning opportunities and science-specific competences, policymakers and professional development providers may ensure that all preschool teachers receive sufficient learning opportunities to further their professional competences.