Marine debris is a major problem for ocean life, so it’s important to find ways to manage and reduce it. We used eight years of community-collected data before Queensland, introduced a container deposit scheme (CDS), and three years of data after, to see how the scheme affected local marine debris accumulation. We looked at the amount and types of litter collected in the Whitsunday region, to evaluate the CDS’s effectiveness. Our results indicated a significant drop in CDS-targeted debris, such as plastic bottles and aluminium cans, after the scheme started, suggesting it helps with recycling and reducing litter after a very short time. However, the overall amount of other types of marine waste didn’t change, indicating that while the CDS is a good start for reducing certain litter types, we need broader waste management strategies to tackle marine pollution fully. This study highlights the importance of community science data in evaluating environmental policies and supports the idea that CDS is a useful tool for reducing marine debris.