Japan enacted a new teacher education curriculum in 2019, following which it became possible to include school experiences and internships within one's practicum credits. However, the contents of the practicum are not systematically arranged, and discussions on student-teachers' (STs) learning and their resulting professional development achieved through the practicum are limited. The purpose of this study is to identify and examine the challenges STs faced in their initial school experience, with a particular focus on STs who began their teacher education programme. Twenty-eight STs attending the early stages of a teacher education programme participated in this qualitative case study. The findings suggest that STs have recognised their own challenges regarding understanding students, teaching skills and methods, and active communication. In addition, the results re-confirm the value of early school experience in teacher training. Particularly, the results suggest that the first school experience can help STs realise the importance of acquiring the knowledge and skills necessary to know and act like a teacher, and the importance of theoretical learning at university.