Promoting the sustainability of the COSMOS approach in schools involves fostering an environment where open schooling and Socio-Scientific Inquiry-Based Learning (SSIBL) are embedded into school culture, curriculum, and community partnerships. The sustainability of a project refers to its ability to maintain its outcomes, benefits, and operations over the long term, without requiring continuous external resources or support beyond its initial funding or setup. A sustainable project is designed to continue delivering value and meeting its objectives after the project lifecycle, ensuring lasting positive impacts. This section provides insights and actionable steps for teachers, school leaders, and policymakers to ensure the COSMOS approach remains effective and impactful.