Community waste banks are a widespread phenomenon in Indonesia, providing small scale waste reduction whilst creating financial value for the community. Semarang has over 200 community waste banks. This case study describes its challenges and opportunities, using different examples that demonstrate how to create co-benefits from waste banks. This case study has been developed as part of Urban Ocean, one of Resilient Cities Network’s multi-city programs, co-designed and delivered with our partners Ocean Conservancy and The Circulate Initiative. Urban Ocean supports cities in assessing their risks and vulnerabilities as well as gaps in their waste management systems that lead to plastic leakage into the environment and the ocean. It helps cities to identify actions, design better projects and innovative solutions, leverage partnerships, and finally connects cities and their projects to potential funding sources.