Teaching practice is critical to teacher education as it provides the pre-service teachers with practical experience of professional responsibilities and classroom practices, which are basic foundations for their choice of teaching as a profession or career. It is mandatory for pre-service teachers to experience teaching practice as a requirement in teacher education to acquire practical teaching competence in schools. Students in teaching practice are required to be mentored by their subject teachers in the schools. Thus this study investigates subject mentors' perceptions of Post Graduate Certificate in Education (PGCE) students' teaching practice lived experiences to determine their readiness for professional classroom practices. Competence and readiness to teach are inseparable because the latter demonstrates the skills which pre-service teachers display when delivering certain aspects of their teaching. Hence teaching is incomplete without teaching practice. Five subject mentors who were mentoring PGCE student teachers were purposively selected and engaged in semi-structured interviews for the data collection for this study. Content analysis was used to identify themes and analyse the data. The findings revealed, among others, that PGCE student teachers do not have adequate pedagogical content knowledge. Based on the findings, the study, therefore, recommends that the training for PGCE students has to be increased from one year to two years to acquire the appropriate knowledge and skills.