This article examines Mapa Verde, a participatory digital mapping project co-created by young environmental activists and academic researchers in Uruguay between 2023 and 2025, from the perspective of participatory action research along with social and technopolitical cartography. Drawing on the observation and systematization of collaborative workshops, revision of periodical reports of activities and outcomes, and in-depth interviews with the young activists involved in the participatory cartography, the article reconstructs and interrogates the co-creation process: diagnosis, construction, and evaluation (Calvo & Candón-Mena, 2023). It also analyzes youth imaginaries regarding digital media activism and environmental advocacy through counter-mapping. Pragmatic and critical imaginaries of digital media for activism are found among the young participants who created Mapa Verde, while the collaborative enterprise reflects community-based communication and some traces of counter-data mapping that strengthen identity and foster inter-organizational collaboration. The project expands participatory cartography practices in political ecology and environmental communication, highlighting youth as both agents and cartographers of environmental action. The process shows that mapping is not only a technical exercise but also political, cultural, and pedagogical, enabling new forms of participation and knowledge production