Slum population has increased continuously in global south. It expands onto precarious land such as floodplains, lagoon areas and so on leading to deficiency of basic facilities. Bandung is the third most populous city in Indonesia with around 26,000 slum dwellings. Kampung Tamansari in Bandung is the densest informal settlement located along the Cikapundung river. During the Dutch colonial era, this area was meant to be a part of the green corridor under the Garden city scheme. However, the concrete mass now uprooted the green. However, since the area is located at lower level than planned area, it is hard to expand existing infrastructure into the area. Lack of infrastructure in informal settlements and densification have led to the environmental degradation and have disconnected people from nature. Treating the river as an open sewage, people directly discharge their waste into it. Clogged ditches with garbage as well as cemented pavements which restrains water from going into the soil results in flash floods. Therefore, nature and human activities enter a vicious cycle which requires the redefinition of this relationship. This research aims to reconnect people and nature by improving their living quality through ecosystem service. It is based on two main research fields. First, Ecopolis gives a structure to create self-governing ecologically sustainable city. Tjallingi’s Ecopolis strategy helps to look into the site based on three different perspectives: area, flow and participation. Kampung Naga is used as a case study to understand how Indonesian cultural landscape creates a circular water system. Next, Kampung Tamansari is used as a showcase to explore how the ecopolis strategy can be applied into the context of a developing country. It shows how people can change their recognition of the potential of nature and how can their activities positively influence in nature in a long-term. The design strategy starts from place making for green spaces. Relocation is considered in this stage. Relocating houses are arranged in North Kampung as creating three types of enclosures (enclosure, semi-enclosure, expanded semi-enclosure). Each enclosures are transformed into different green patches to serve different ecosystem service and make people responsible to maintain the spaces. Green patches consist of kitchen garden, pit-forest and riverfront park. Kitchen garden is built in enclosure space which offers basic facilities using dry-toilet module which can recycle human faeces, generate electricity and store rain water. It lets people create their own kitchen garden to overcome food insecurity. Pit-forest is permaculture system using plant-based ecosystem service combined with organic waste management. River front park is the most open space which connects people to the river. Furthermore, it shows users visible circular water system. On the other hand, these three green patches work together as one stormwater management system. It links each other and create complementary network. Moreover, it transforms current highly linear water flow into circular water flow. This green patch strategy can be applied to other informal settlements in the similar contexts. When it is replicated, it will not only build rich ecosystem service in the informal settlement but also create mosaic garden city, Bandung in a city scale.