Out-of-field teaching occurs in schools and education systems worldwide. Early career teachers are more likely to be required to teach out-of-field and also to experience adverse effects from this experience, potentially contributing to workforce issues and teacher attrition. This mixed data Australian study reports on the perceptions of preservice teachers--emerging professionals-- regarding issues associated with out-of-field teaching. Survey data were collected from 133 preservice teachers. Data were analysed with an initial layer of sentiment analysis followed by a thematic analysis of their perceptions of consequences for teachers, students, and schools/communities. Findings reveal that preservice teachers are very aware of the mostly negative consequences of out-of-field teaching. The practice has implications for initial teacher education, for policymakers seeking to address teacher workforce issues, and for school and system leaders managing a profession that is high stakes in relation to student outcomes and high stress in relation to professional demands.