The study explored the best practices of winning Science Investigatory Projects (SIP) coaches in Region XII for the last five years, within School Year 2019-2020. Qualitative research was employed using interviews and focus group discussions (FGD). The data gathered on the best practices of winning the Science Investigatory Project (SIP) in Region XII were analyzed using narrative analysis (Creswell, 2007). Four themes were formulated based on the responses of the participants.                The findings reveal that SIP Coaches/Advisers in Region XII have implemented best practices which enabled them to produce winning entries in SIP competitions. These best practices include setting of criteria in the selection of advisee for science investigatory project conduct of school-based science fair/competition implementation of school-based curriculum on SIP Setting of Criteria in the Choice of the Topic for SIP enhancing the Research Skills of Advisees/Mentees provision of on-line educational resources for students researches motivation and inspiration of the advisees by the coaches mentoring/preparing the researcher before and during the SIP competition and developing good researchers, as a legacy of the coaches. The study also disclosed that SIP coaches encountered some challenges/problems in the process of mentoring their advisees, such as: financial concerns time constraints lack of school and administrative support pressure from colleagues advisees attitude and lack of laboratory resources and other materials. However, they were able to address these challenges/problems by implementing some interventions and strategies.