Purpose: This study examines how participatory, community-based social work interventions can promote pro-environmental behavioral change among residents of the Musi River in Indonesia. Method: A 6-month participatory action research design was implemented across three riverine communities. Data were collected from N = 40 participants using in-depth interviews, focus group discussions, participant observation, and behavioral surveys. Results: The intervention led to substantial shifts in reported environmental behavior, strengthened collective norms, and the emergence of a shared ecological identity. Residents demonstrated increased participation in river stewardship, peer-based monitoring, and localized environmental leadership. Discussion: The findings underscore the transformative potential of community-based social work in addressing environmental degradation. Through culturally grounded engagement, social workers functioned as facilitators of normative and structural change. This study contributes to advancing ecosocial frameworks within global social work practice, particularly in under-resourced urban contexts.