This study focuses on the vocational interests of trainee teachers for kindergarten and primary school, investigating whether the RIASEC-interest dimensions are related to teaching preferences in the Swiss subject of Nature–Human–Society, which is characterized by its multidisciplinarity. Interests are a source of individual differences in people and important to study since they influence intrinsic motivation, and thus, behavior, effort, and occupational decisions. The results of the conducted survey, composed of the Nature–Human–Society questionnaire and the general interest structure test (AIST-R), show, in a sample of 220 participants, that trainee teachers’ vocational interests were partly related to their previous experiences in the specific content domains of Nature–Human–Society and slightly differed by gender. The RIASEC interest dimensions of social, investigative, realistic, and partly artistic evidence significant correlations with preferences in the teaching topics of the Nature–Human–Society subject. It became clear that trainee teachers with high realistic and investigative interests and low social and artistic interests tended to prefer thing-related teaching topics, while pronounced social and artistic interests with low realistic and investigative interests were associated with teaching preferences for people-related topics in the subject of Nature–Human–Society. The dominant role of Prediger’s people- versus thing-related interest orientation could thus also be confirmed in the choice of favorite teaching topics, signaling that teachers feel comfortable with those topics that match their interest structure.