The title of S3, E2, Ocean Optimism, does not imply that nothing is wrong with the Ocean, just that progress made in solving marine conservation challenges shows that there are grounds for hope for the future. Increased industrialisation and urbanisation, increased exploitation of resources, and a decreased resilience to larger threats like climate change have certainly led to a dramatic decline in ocean health, as has been well documented. The UN Decade of Ocean Science (2021-2030) and the UN Decade of Ecosystem Restoration provide a top-down framework for work to prevent, halt and reverse the degradations of marine ecosystems, but there still needs to be a popular, bottom-up, impetus for change if we are going to stop the degradation and restore our 'world ocean conveyor belt' to full health. There are encouraging signs that this is happening.  Ocean Optimism is presented by Mike Elliott, Professor of Estuarine & Coastal Sciences at the University of Hull, UK, and Director of International Estuarine & Coastal Specialists Ltd.  A marine biologist, Mike's teaching, research, advisory and consultancy includes estuarine and marine ecology, policy, governance and management. Now is the time, he concludes, to walk the walk, not just talk the talk. What we truly need to achieve transformative change in ocean conservation, and conservation broadly, is nothing less than a social revolution. And are we prepared to make the commitment, to shoulder the costs of the energy transition, to fund protection and restoration on a global scale, and accept major changes in our diet? Mike's interview is a narrative that can inspire others to join in that transformative effort.