SUBMERGE aims to strengthen the quality, credibility, and innovation of youth work in the field of environmental education, with a specific focus on aquatic ecosystems. In recent years, topics such as biodiversity loss, freshwater degradation, the blue economy, and climate adaptation have become increasingly relevant in youth work. However, youth workers often lack practical tools to translate complex scientific knowledge into engaging, responsible, and evidence-based non-formal learning activities. The objective of SUBMERGE is to bridge this gap between environmental science and youth work practice. The project will equip youth workers with the competences needed to interpret environmental data, understand aquatic ecosystem dynamics, and communicate scientific knowledge with an inclusive approach. At the same time, it will strengthen their ability to design participatory workshops grounded in environmental evidence and to guide young people in critically reflecting on misinformation, environmental narratives, and technological solutions such as AI-based species recognition with underwater cameras. From the perspective of youth work practice, SUBMERGE focuses on three concrete objectives. First, to increase youth workers’ confidence in working with scientific content related to freshwater and marine ecosystems. Second, to provide tested, ready-to-use educational tools through the co-creation of the SUBMERGE Educator Guide. Third, to strengthen professional recognition of youth workers as competent facilitators of science-based sustainability education. By combining field-based learning at Lake Balaton in Hungary and Lake Sevan in Armenia, scientific input from research institutions, and participatory non-formal methods, the project offers a structured and practical solution. Youth workers will return to their organisations better equipped to design and implement high-quality environmental programmes, contributing to more informed and engaged youth participation in sustainability topics.