The purpose of this study was two-fold. Firstly, it examined how preservice primary teachers develop self-assessed technological, pedagogical, and content knowledge (TPACK) in science through an intervention in which they were acquainted with using simulations in science teaching. Secondly, it studied the possible connection of preservice teachers’ beliefs measured through their self-assessed knowledge in the different domains of the TPACK framework with their attitudes toward simulations. The results indicate that the introduction to simulations in science had a medium to large effect on the preservice teachers’ beliefs in the content knowledge (CK), pedagogical knowledge (PK) and TPACK domains of the TPACK framework. Preservice teachers’ belief in their technological knowledge (TK) correlated with their views on the usefulness of simulations in science teaching.