Many countries are facing a shortage of science teacher candidates; thus, it becomes increasingly important to understand science preservice teachers' (PSTs') career entry motivations because it plays an important role in attaining and retaining talented science teachers. This study therefore aims to explore and compare science PSTs' motivations and perceptions about the teaching profession in different contexts and to understand the role of gender and study subjects regarding motivation. Data collected for this study from two countries, Finland and Korea, are analysed using latent mean analyses. According to the results, Korean PSTs indicate a lower level of confidence and satisfaction in their career choice than their Finnish counterparts. Female PSTs, when compared with male PSTs, perceive themselves to have lower levels of ability and interest in teaching and view a science teaching career as more difficult and demanding. Finally, the results show that biology major PSTs possess higher altruistic motivations than those with other science majors. Findings of the current study suggest that (1) science teacher candidates benefit from studying pure science before becoming involved in a teacher training programme, and (2) PSTs' motivations and perceptions, especially females' and non-biology PSTs', need to be carefully monitored.