City beaches are produced by spreading sand, deckchairs and umbrellas onto industrial brownfields, parking lots, rights-of-way or other under-utilized open spaces. Where major reinvestment projects are lacking, these informal developments offer great amenity. This approach to placemaking is post-Fordist. It is highly flexible, even mobile. It involves complex, temporary networks of people and resources. It focuses on ‘soft’ content—services, programmes, themes, atmosphere—rather than inflexible built form. This enables rapid innovation. Through four case studies, the paper explores the roles and relationships among diverse actors—city mayors, entrepreneurs, property developers, grass-roots organizations, think-tanks and planners—in the production of city beaches, and identifies what new policies, tools and management approaches they require.