This report describes federally funded ocean acidification activities during fiscal years 2020 and 2021. The report describes projects that were funded across the federal government, organized by region and then by thematic area. Budget tables are included that detail the amount spent by each agency on each thematic area. From these investments, advancements were made in understanding ocean acidification and its impacts, including in the following areas: Agencies increased co-located chemical ocean acidification and biological monitoring, including eDNA sampling, and funded research to identify potential bio-indicators. New investments were made in coastal acidification monitoring and in research on processes, such as land-based inputs that contribute to the variability in the coastal zone. Agencies funded models that considered OA impacts to economically valuable species, including oysters, Dungeness crab, and Pacific cod. Agencies supported new curriculum development and educational workshops for students of various ages.