Teachers' pedagogical content knowledge (PCK) and professional vision (PV) are assumed to influence instructional quality. However, little is known about the development of these competences and their interplay, particularly in elementary science education. Therefore, this longitudinal study investigates the development of PCK and PV elementary science during initial teacher education in Germany and the interplay of both developments. We examined 99 preservice teachers over three years, including their master's degree program at university and a mainly practical induction phase in school. Results indicate that PCK and PV increased during the university phase. In the induction phase, PCK slightly decreased whereas the development of PV stagnated. Although the developments of PCK and PV were related in both phases, the correlation at university phase was stronger.