<p>This longitudinal study with two measurement points examines changes in the professional identity of prospective primary school teachers. An online questionnaire was used to collect data from prospective primary school teachers studying mathematics and German at the beginning of their studies (<i>N</i> = 151) and after four semesters (<i>N</i> = 101). The results show that actual and designated identities changed over time, with the roles of subject specialist and didactician being more strongly emphasized than the roles of developmental psychologist and social pedagogue. Positive correlations were found between actual identity as a subject specialist, academic self-concept and enthusiasm for the subject. In addition, positive correlations were found between the actual identity as a subject specialist and didactician and the corresponding designated identities and satisfaction with the corresponding courses. The results underline the importance of addressing professional identity more intensively in university education, especially at an early stage of study, in order to adaptively develop and foster the professional competence of prospective teachers and to improve the quality of teaching.</p>