The Water Code – The Formula for the Sustainable Management of the World’s Water Resources is an active global citizenship and sustainability education project, aimed at promoting knowledge, skills, attitudes, and behaviours supporting environmental protection and the sustainable management of water resources. Within the project, outdoor educational activities focused on microplastic (MP) pollution were carried out to actively engage students in scientific research while fostering environmental awareness and a stronger connection with the coastal marine environment. The initiative led by CNR-IAS was carried out in collaboration with Outdoor Portofino, building upon the methodology and results of the previous Micro Plastic Hunters Project. The latter demonstrated the effectiveness of an innovative citizen science approach for monitoring MPs in nearshore coastal environments, using Mini-Mantas, a smaller version of Mant nets (MSFD instrument for MPs sampling), designed to be towed by recreational watercraft. The Water Code project involved 80 students aged 11–14 across the Liguria region participating in field activities to monitor MPs in the surface waters of the Portofino Marine Protected Area. Participants were actively engaged in all stages of the scientific process, from collecting samples using kayaks and Mini-Manta nets to analysing them in a field laboratory equipped with microscopes, supported by CNR-IAS researchers. This experience transformed scientific learning into a hands-on emotionally engaging journey, allowing students to explore local marine ecosystems while contributing to real research activities. The results highlight the educational value of experiential and outdoor learning approaches in promoting scientific literacy, critical thinking, and responsible environmental behaviours. Furthermore, the initiative demonstrates how citizen science can strengthen the relationship between schools, research institutions, and local communities, fostering active participation and a deeper sense of stewardship toward nature and coastal environments.