Blue spaces, natural and human-made inland and coastal waters, are associated with numerous threats to health and well-being, from flooding and drowning to various forms of pollution, and invasive species. However, they also offer many potential benefits, with physicians prescribing spending time in and around natural waters for millennia. This talk will summarise the key findings from a 15-year programme of work (spanning several multi-country funded projects) studying the links between blue spaces, health and resilience using multiple research methods including epidemiological studies of census data and longitudinal medical and survey cohorts, economic assessments of relevant ecosystem services, randomized controlled trials, and place-based field interventions. Although early work focused on UK coastal waters, subsequent efforts have expanded this to inland waters and settings across Europe, North America, Australia, and Asia. The talk will present evidence of the mechanisms behind how blue spaces, including various Nature-based Solutions (NBSs), support good health and well-being (including through mitigating the effects of climate change), discuss moderating effects that affect these processes, and highlight a range of interventions such as Nature-based Therapies (NBTs) to promote greater contact with blue spaces to promote health, well-being, and resilience among targeted populations and communities.