Marine debris is a growing global problem that poses health and safety hazards for humans and animals. Efforts to manage marine debris include beach clean ups and citizen science, a scientific method that incorporates community members in the data collection process. Citizen scientists have used geographic information systems (GIS), a process to visualize data and trends in the forms of maps, in order to conserve and manage their environments. Furthermore, participatory geographic information systems (PGIS) allows for the visualization of local knowledge through maps and has been used extensively to identify potential sites with problems and to influence conservation management in terrestrial areas, however, it has rarely been used in marine environments. PGIS provides spatial data from the community that is often excluded in ecological studies. Therefore, the purpose of this study was to integrate local knowledge from community members with field data to examine marine debris in Hopkins Village, Belize. We investigated the distribution, abundance, and perceptions of marine debris using PGIS, quantitative beach surveys, and interviews. The ArcCollector mobile mapping application was used to collect data on beach characteristics and debris within a 4x4 meter quadrat every 50 meters along the coast. Qualitative interviews were conducted to understand the community’s perceptions of marine debris and proposed solutions. Finally, ArcCollector was used with 101 participants to map areas in Hopkins they valued and believed had the most abundant debris. The vulnerable areas identified by each participants were aggregated into one map using ArcGIS Desktop. The results showed most participants valued recreational regions, specifically the school and pier. From the beach surveys, the school and pier had an abundance of natural and plastic debris, which is also consistent with community perceptions. Furthermore, there was a significant difference between land use and amount of debris. Our results provided geospatial data, in the form of physical maps, for Hopkins to focus their mitigation efforts in areas the community identified. Through the mixed method approach and bottom-up framework, marginalized communities share their knowledge about problems scientists are trying to mitigate, such as marine debris. Collecting this data from communities is imperative to creating sustainable solutions within these developing regions. Furthermore, mixed methods approach can be used to identify and solve local environmental issues in other developing countries.