Significant advancements have been made over the past four decades in understanding and quantifying the stocks and flows of carbon between the reservoirs. However, knowledge of the complex oceanic processes influencing the carbon cycle has been largely compartmentalized into physico-chemical and biological studies. The connections between coastal and open-ocean carbon processes have also been understudied. To fully appreciate the ocean carbon cycle, and its anticipated changes in the future, a holistic and integrated approach to ocean carbon cycle research is needed. In particular, a greater quantitative understanding of how biological processes interact with the physical and chemical drivers in the open ocean and in coastal waters is needed. Moreover, the carbon cycle needs to be understood in the current socio-economic context and large anticipated changes in the next decades. To address these issues, the Integrated Ocean Carbon Research (IOC-R), a formal IOC working group, was formed in 2018. The working group is a response to the UN Decade of Ocean Science for Sustainable Development 2021-2030, “the Decade”. The IOC-R will contribute to the science elements of an overarching Implementation Plan for the Decade. The Implementation Plan is a high-level framework to guide actions by which ocean science can more effectively deliver its contribution to achieving the societal outcomes outlined for the Decade. The IOC-R focusses the ocean carbon cycle component of the Implementation Plan by addressing key issues in ocean carbon research through a combined strategy of research and observational goals. The research will be framed by four key questions that were formulated at the inaugural Expert Workshop on Integrated Ocean Carbon Research at the IOC-UNESCO Headquarters in Paris, France on Oct. 28-30, 2019: 1) Will the ocean uptake of anthropogenic carbon dioxide (CO₂) continue as primarily an abiotic process? 2) What is the role of biology in the ocean carbon cycle? 3) What are the exchanges of carbon between the land-ocean continuum and how are they evolving over time? 4) How are humans altering the ocean carbon cycle, and what are the feedbacks?