The 4th Evolving and Sustaining Ocean Best Practices Workshop was held online during the period 17-30 September 2020, addressing community needs for advanced method development and implementation in ocean observations, data management and applications. The workshop consisted of three plenary sessions and eleven Working Group meetings. These Working Groups, who met multiple times during 21-24 September, included topics in: Convergence of methods and endorsement of best practices Data and information management: towards globally scalable interoperability Developing community capacities for the creation and use of best practices Ethics and best practices for ocean observing and applications Fisheries Marine Litter/Plastics Omics/eDNA Partnership Building Sargassum Surface Radiation Uncertainty Quantification The workshop participants came from across the globe (see Figure 1 under Participants) and had a wide range of interests relating to the ocean. The workshop focused on ways that ocean observing across the value chain (from observations to end user decisions) can use best practices to improve interoperability and our knowledge of the oceans. Ocean practitioners collaboratively addressed best practices as well as recommendations for the Ocean Best Practices System (OBPS) which will guide its next implementation phase. The recommendations (see Section 8) will broaden community engagement and help the OBPS serve the community and advance efforts along the following key dimensions : Data, Information, Knowledge Endorsement of methodological documents by communities Uptake of methodologies by communities Convergence of methods across scales (thematic, local, regional, global) Development paths – how does a region/community build best practices? What does your region need? How can the OBPS better support that? Published Refereed Current 14.A Manual (incl. handbook, guide, cookbook etc)