Mentoring Program is a structured support system proposed in this study that provides guidance, coaching, and professional assistance to non-science teachers handling science subjects. Despite the increasing number of out-of-field teaching assignments, there were limited studies exploring the lived experiences of non-science teachers in the Department of Education Leyte context. This study employed a phenomenological research design and utilized purposive sampling and semi-structured interviews anchored in Pedagogical Content Knowledge (PCK) Theory. The participants consisted of three (3) non-science teachers who were currently or had recently handled science subjects in selected public secondary schools. Data gathered were analyzed through qualitative thematic analysis to identify key experiences, challenges, and coping mechanisms, which were organized into emerging themes. Based on these findings, a context-responsive mentoring program was developed to support non-science teachers in improving their instructional practices and confidence in teaching science. The study benefited students, teachers, science mentors, school administrators, and policymakers, the Department of Education, and future researchers by enhancing science instruction, strengthening mentoring systems, informing policy and administrative decisions, and contributing to the broader field of science education research.