The value of marine debris data collected and made available to stakeholders through various platforms and data infrastructures distributed globally remains limited due to insufficient level of coordination between efforts which deal with data comparability, availability, and quality assurance and control. Establishing a federated data management system complying with data requirements of marine debris research and monitoring and adopting standardized metadata structures would allow data harmonization across different studies, data centers and monitoring programs. Moreover, such an approach would improve the capacity to produce data synthesis products and facilitate global coordination of monitoring and observations, in turn, advancing our capacity for model development, scientific assessments and science-based decision making. Support of international coordination bodies such as International Oceanographic Data and Information Exchange (IODE), the Global Ocean Observing System (GOOS) and GEO Blue Planet, among others, is required to ensure integration into existing global systems and efficient coordination across the entire value chain, from data acquisition to application, also to support the ongoing negotiations for, and future implementation of, a global treaty on plastic pollution. The UNEP Global Partnership on Plastic Pollution and Marine Litter (GPML) Community of Practice on Data Harmonization and the Integrated Marine Debris Observing System (IMDOS) aim to address the above mentioned challenges by promoting harmonization of data acquisition and processing methods, and harmonization of data including associated metadata and data management, in collaboration with the Ministry of the Environment, Japan (MOEJ), EU MSFD Technical Group on Marine Litter, EMODnet Chemistry, and the NOAA NCEI among other potential data centers to establish interoperability to support UNEP’s federated model on the UNEP GPML Digital Platform. These infrastructures have the potential to collect data from research, monitoring by environmental authorities, as well as NGO and citizen science field campaigns, and have the capacity to archive, aggregate and synthesize the data for science and policy applications. The comparability of monitoring data should be enhanced by referring to monitoring guidance and existing large scale monitoring schemes, such as guidance made by the GESAMP, the EU MSFD Technical Group on Marine Litter, and MOEJ under the G20 Implementation Framework for Actions on Marine Plastic Litter.