How big was the loss of professional competence development of prospective teachers in field experiences during the COVID-19 pandemic? To quantitatively estimate the effects of school closures in early 2020 on the outcomes of field experiences, we conducted comparative analyses of the development of perceived teaching competence of teacher students in a one-semester school internship. Prospective teachers in the internship affected by COVID-19-related school closures showed a significantly lower development of perceived competencies regarding teaching skills, classroom management and assessment compared to prospective teachers in the previous typical internship, but a greater development of perceived ICT-competencies. However, when pandemic-affected teacher students were involved in new forms of teaching with their school mentors, hardly any differences to a typical internship were observed.