Utrecht Youth Network (UYN), by time of application an informal group, but grown into a NGO, coordinated its first Erasmus+ mobility project for youth workers with the aim of strengthening sustainability-focused youth work across Europe. HarmonyBuilders: Empowering Youth for a Greener Future was designed to address the urgent need for climate education and to equip youth workers with practical, non-formal tools to engage their communities, and especially young people with fewer oppurtnuities, in environmental action. The objectives of the project were to: - Highlight pressing ecological challenges globally and within Europe, and explore how our daily lifestyles contribute to climate change — while promoting collective thinking around these topics. - Evaluate and share the most promising ecological strategies and youth work methods that can be adapted to the participants’ local realities. - Draw attention to SDG 13 (Climate Action) and explore how youth work can directly contribute to achieving this goal. - Share practical and non-formal educational tools — such as upcycling, ecological footprint tracking, and zero-waste practices — that youth workers can integrate into their daily work. - Introduce the Erasmus+ programme and Youthpass as tools for international learning, local impact, and personal development. - Boost the capacity of youth workers with fewer opportunities through peer-based learning and inclusive facilitation, improving their participation in the Erasmus+ programme and their access to future opportunities. - Develop sustainable initiatives that youth workers can take back home and implement with at-risk and marginalised youth, with a focus on long-term community engagement.