Navigating the Future is a publication series produced by the European Marine Board providing future perspectives on marine science and technology in Europe. Navigating the Future V (NFV) highlights new knowledge obtained since Navigating the Future IV (2013). It is set within the framework of the 2015 Paris Agreement and builds on the scientific basis and recommendations of the IPCC reports. NFV gives recommendations on the science required during the next decade to deliver the ocean we need to support a sustainable future. This will be important for the United Nations Decade of Ocean Science for Sustainable Development (2021 – 2030), the implementation of the UN Sustainable Development Goals and the European Commission’s next framework programme, Horizon Europe (2021 - 2027). There is a growing need to strengthen the links between marine science, society and policy since we cannot properly manage what we do not know. In recent years, the ocean and seas have received new prominence in international agendas. To secure a safe planet a priority is the management of the ocean as a “common good for humanity”, which requires smarter observations to assess of the state of the ocean and predictions about how it may change in the future. The ocean is a three-dimensional space that needs to be managed over time (thus four-dimensional), and there is a need for management and conservation practices that integrate the structure and function of marine ecosystems in these four dimensions. This includes understanding the dynamic spatial and temporal interplay between ocean physics, chemistry and biology. Multiple stressors including climate change, pollution and over-fishing affect the ocean and we need to better understand and predict their interactions and identify tipping points to decide on management priorities. This should integrate our understanding of land-ocean-atmosphere processes and approaches to reducing impacts. An improved science base is also needed to help predict and minimize the impact of extreme events such as storm surges, heat waves, dynamic sea-floor processes and tsunamis. New technologies, data handling and modelling approaches will help us to observe, understand and manage our use of the four-dimensional ocean and the effect of multiple stressors. Addressing these issues requires a strategic, collective and holistic approach and we need to build a community of sustainability scientists that are able to provide evidence-based support to policy makers within the context of major societal challenges. We outline the new frontiers, gaps and recommendations needed to manage the ocean as a common good and to develop solutions for a sustainable future. The governance of sustainability should be at the core of the marine research agenda through co-production and collaboration with stakeholders to identify priorities. There is need for a fully integrated scientific assessment of resilience strategies, associated trade-offs and underlying ethical concepts for the ocean, which should be incorporated into decision support frameworks that involve stakeholders from the outset. To accurately assess the state of the ocean and make predictions for the future, research programmes should be co-designed with stakeholders. Achieving the ocean we need for a sustainable future by 2030 will require sustainability science, which is holistic and transdisciplinary. To allow the collection, processing and access to all data, a key priority is the development of a business model that ensures the long-term economic sustainability of ocean observations.