In the United Kingdom of Great Britain and Northern Ireland, retiring to the coast has long been very popular, and its beneficial effect on all ages is now well documented. As part of a focus of international research, the United Kingdom of Great Britain and Northern Ireland is investigating exactly how far marine and coastal settings support public health and help to tackle inequalities through physical activity on land or water. Data from two large, multiwave population representative datasets, the Health Survey for England and the Monitor of Engagement with the Natural Environment, revealed that approximately 271 million recreational visits were made each year in 2009–2016 to coastal environments in England (United Kingdom of Great Britain and Northern Ireland). Every year since 2009, about 45 000 interviews have been conducted by the Monitor of Engagement. In terms of welfare gains, the annual benefit of water sports alone is estimated to be in the order of £176 million, with considerably higher benefits from more frequent on-land activities, such as walking and running along beaches and coastal paths. More recent work using the Health Survey for England has again demonstrated that this activity has positive outcomes mentally and physically (T Pasanen, unpublished data). These studies highlight the need to protect and manage marine and coastal environments for the benefit of human health and well-being. Similar findings have been seen in Asia, Australia, Europe and North America. Local and national authorities, health-care providers, communities and other partners now have the opportunity to promote public health and prevent disease by creating and maintaining healthy blue spaces that are accessible to all, leaving no one behind. The research findings to date largely stem from developed countries, so future research needs to explore whether the same benefits to health and well-being are found in developing countries. This is particularly important for the very poor populations living in many coastal areas globally threatened by marine pollution, climate change and the associated risks of flooding, storm surges and poor water quality.