This paper explores the competencies of Life Sciences pre-service teachers in Education for Sustainable Development (ESD), following UNESCO's 2030 call to address global sustainability challenges. Effective ESD integration requires teachers to be adequately prepared, yet higher education often falls short in equipping future educators with essential ESD competencies. Using a qualitative, interpretivist approach, the study analyzed semi-structured interviews and micro-lesson observations of four South African pre-service teachers. Thematic analysis revealed two main themes: perspectives on ESD and the facilitation of ESD in Life Sciences through Pedagogical Content Knowledge (PCK). To enhance the trustworthiness of the findings, data triangulation and member checking were employed. Findings indicate limited awareness and pedagogical application of ESD principles among participants, underscoring the need for targeted training and enhanced alignment of teaching practices.