The Monitoramento Mirim Costeiro (Junior Coastal Monitoring Program) is a pioneering citizen-science program where students become scientists and leaders in environmental preservation within their community. By directly engaging students with current ocean issues, the program aims to transform them into ocean citizens and agents of change within their communities. Students participate in all research steps, including data collection, analysis of information, and communication of results. The project, which started in a small fishing village called Garopaba in southern Brazil, is gradually expanding worldwide and has already benefited more than 5,600 students and 270 teachers across 20 municipalities in Brazil and Portugal. Our mission is to form a vast network of Junior Ocean Guardians. That’s why, since 2012, we have been training children and teachers to care for our seas. As a project of the Ocean Decade, our commitment to raising awareness among as many children as possible around the world is further strengthened, contributing to the nurturing of a more committed and active generation in ocean preservation.