Swimmable Cities: Connecting Urban Life with Water - And Why It Matters for Climate Action

Cities around the world are reopening rivers, canals, and harbors for everyday swimming, reclaiming the right to water as public space. Inspired by Paris’s effort to clean the Seine for the 2024 Olympic Games and by the launch of the Swimmable Cities Alliance, 83 cities and towns and 30 countries across the globe have pledged to restore their waterways and make them safe, clean, and accessible for all.

The movement has drawn attention to the essential role of water in our urban environments. But beyond swimming and creating more livable cities, the bigger question is: what impact can swimmable cities have on climate change?

The urban–ocean connection we often overlook

We often hear the Earth described as either the Urban Planet or the Blue Planet. The Urban Planet reflects a world where more than half of our population already lives in cities, a share expected to rise to two-thirds by 2050. The Blue Planet, by contrast, refers to the the fact that 70% of our earth’s surface is covered by water, with the oceans holding about 95% of it. These two 'planets' are rarely spoken of together, yet they are deeply interconnected.

In our cities, we depend on water, water that at some point in its lifecycle has passed through the ocean and is dependent on its health and existence. Most cities have direct or indirect connections with the ocean, whether through seas, lakes, rivers, or canals. In fact, many cities were built around waterways that enabled goods to be transported across the ocean and inland. Beyond their economic and technical roles, water bodies bring life to cities, offering residents points of connection with nature and a sense of awe.

We know that cities concentrate energy use, materials, and waste, and therefore produce a large share of greenhouse-gas emissions. Despite benefiting from water bodies, urban and industrial runoff as well as wastewater carry nutrients, chemicals, pathogens, plastics, and heat into oceans directly or travel there through inland waterways, impacting freshwater and marine ecosystems both locally and globally. Patterns of urban consumption and production, combined with a growing disconnection from food sources, also drive agricultural practices that harm ocean health. Fertilizers, pesticides, and manure pollute waterways with excess nutrients, sediments, and toxic chemicals, causing eutrophication and dead zones, habitat destruction, and harm to marine life. Added to these land-based pressures, urban demand for seafood contributes to overfishing and the erosion of marine biodiversity.

Despite this feedback loop, urban residents often feel distant from the ocean. A recent study highlights that people underestimate the importance of the ocean’s health in tackling climate change. Swimmable-city projects help close that gap by making local waterways visible, accessible, and part of daily life. When people regularly engage with a river or harbor, expectations for water quality rise, and so does the political will to invest in the infrastructure that protects it.

From blue urbanism to practice

Urbanist Timothy Beatley calls this way of thinking blue urbanism: a planning approach that expands the boundaries of cities beyond the land, encouraging urban areas to design with water in mind, whether it’s a river, lake, wetland, or the ocean.

In recent years, much of the focus has been on coastal cities and their relationship with the sea through the “ocean city” concept. In Plymouth, for example, the UK’s first National Marine Park was established to improve public access to the waterfront, enhance ocean literacy, and restore marine habitats. Restoration initiatives such as seagrass planting and oyster bed recovery are paired with opportunities for public swimming, linking ecological renewal with everyday urban life. In New York, similar efforts are underway through the 'Billion Oyster Project' which engages the public in restoring oyster reefs and raising awareness about the ecological role of oysters in the city’s waterways. Rotterdam, Oslo and Copenhagen have integrated swimming into city planning, combining wastewater treatment upgrades, nature-based waterfront designs, and public amenities.

But the idea of “ocean cities” and blue urbanism should not be limited to coastal locations. Most urban areas, whether connected through coastlines, rivers, or lakes, have some form of direct or indirect link to the ocean and its health. With the Olympic Games in Paris and the launch of the Swimmable Cities movement in 2024, we see greater public attention on this linkage, especially from inland cities embracing the concepts of blue urbanism and recognizing that their waterways are equally critical to environmental health, urban resilience, and community life.

The Swimmable Cities movement

Paris’s commitment to cleaning the Seine for the Olympics helped push the conversation further, proving that even highly polluted urban rivers can be transformed. The Swimmable Cities Alliance, launched on the eve of the Games, has since expanded with both coastal and inland cities joining including Melbourne, Berlin, Budapest, Vilnius and Sheboygen. Besides pollution hazards, many rivers have historically been closed off to their residents due to legal frameworks and insurance concerns. Yet, examples from Basel and Berne show that this does not have to be the case.

The Swimmable Cities Alliance emphasizes the right to swim in clean urban waters, the intrinsic value of the water as living systems, and the role of swimming places in public health, social connection, and intergenerational stewardship. In that, it is also a learning platform and a means for cities to exchange feasible approaches to making rivers swimmable and accessible. Importantly, the movement frames swimmable waters as part of climate resilience, spaces that help communities adapt and thrive amid environmental change.

How swimmable cities support climate action

So what impact can swimmable cities have on climate action? The Swimmable Cities Alliance reminds us that residents share a responsibility for the waters that shape their lives. Its final principle declares: “Urban swimmers are stewards responsible for protecting the health of their local waterways, working alongside Mother Earth’s closest carers.” This highlights the deep interconnection between our planet’s health, local water bodies, and urban communities, and it gives direct stewardship to local people in transforming our cities into socio-ecological ecosystems.

At their core, swimmable urban waters are a sign of healthier urban ecosystems. Clean rivers, canals, and seas mean that pollution is being intercepted, treated, or prevented before it enters larger water systems. This reduces the flow of nutrients, pathogens, and plastics into our oceans. When these efforts are combined with restoration practices in both freshwater and marine ecosystems, the impact goes far beyond water quality for swimming. They help bring back life underwater, strengthen ecosystems’ ability to absorb carbon, and create natural buffers against floods.

Together, these actions support the recovery of aquatic habitats and the stabilization of the natural systems that sustain our oceans. And why does that matter for climate action? Because the ocean is the main player in the global climate system. It dominates the Earth’s heat, carbon, and water budgets, making it the planet’s most important stabilizing system, far more influential than land or atmosphere alone. The flipside is that as the ocean absorbs this enormous burden, it experiences stress: warming, acidification, deoxygenation, and ecosystem collapse. If this balance tips, the ocean system destabilizes, and with it, the entire climate system

Despite its immense role, we often underestimate the ocean’s significance and even its sacredness. This is where the potential of the Swimmable Cities movement comes in. More than an invitation to swim, it offers a way to restore our relationship with the waters around us, whether rivers, canals, lakes, or the ocean itself. By recognizing how urban practices affect local waterbodies, and how those waters are connected to the ocean, we begin to see our direct role not only in driving climate change but also in shaping climate solutions.

In practice, swimmable cities can use their momentum to turn rivers and canals into platforms for learning. By integrating cultural and educational programs, swimming spaces can become classrooms for ocean literacy, illustrating how the health of our cities is inseparable from the health of our oceans. Such initiatives can help restore our cultural connection with the sea by nurturing urban–ocean stewardship and fostering a more responsible, compassionate relationship with oceans and life under water. This growing awareness, in turn, can inspire both residents and local governments to make more climate-conscious choices.

Swimmable cities make climate action tangible:

They turn the abstract idea of climate change into something you can see, feel, and even dive into. They remind us that urban and ocean health are not separate but part of the same living system. And by changing our relationship with the waters right in front of us, we also change our relationship with the ocean and the climate challenges that lie ahead.

Photo by Samuel Girven on Unsplash

Photo by Stepan Konev on Unsplash