Cities around the world need to rethink the way they deal with water and develop into water smart cities. This chapter will address a shift in urban water management towards water smart cities using three strategies: (1) restore degraded ecosystems in natural surroundings of cities; (2) implement Nature-Based Solutions (NBS) on a large scale; (3) close the urban water cycle and treat water as a resource. NBS are solutions inspired by, supported by or copied from nature. The Water Smart City approach integrates urban water management on a district, city and catchment scale. Furthermore, innovation and close collaboration between local stakeholders, businesses and research institutes are a key part of this approach, to continuously learn and improve the solutions. By collecting and analysing data, cities can create an evidence base for nature-based adaptation. Case studies presented are Oslo, New Delhi and Ho Chi Minh City. The chapter concludes with a roadmap to become a Water Smart City.