While urban adaptation projects are designed to protect urban residents, their differentiated impacts on communities warrant critical scholarly attention. This dissertation contributes to deepening our understanding of why particular forms of adaptation prevail over others in different contexts and the implications for social and environmental justice by examining the planning, promotion and contestation of Jakarta’s planned Great Garuda Sea Wall (GGSW) project. Drawing on a critical discourse analysis of the project master plan and supporting engineering and financial reports and documents, press releases, policy documents and legislation, and news articles from local and national sources, as well as 60 in-depth interviews with consultants, bureaucrats and activists conducted during seven months of cumulative fieldwork in Jakarta and the Netherlands, I examine how different environmental imaginaries, situates forms of expertise, and discourses are mobilized by consultants, bureaucrats, and activists in debates concerning flood mitigation. Chapter 2 examines how the GGSW project retains its allure as the optimal solution for Jakarta, despite failing to address what is understood to be a primary cause of flooding: land subsidence. Drawing on the theoretical insights of science and technology studies, urban political ecology, and postcolonial urban theory, I contribute to understandings of the political and economic forces that drive large infrastructure projects. While Chapter Two illustrates the broader structural processes driving the project forward, Chapter Three documents the processes of articulation between Dutch consultants and Indonesian bureaucrats. I interrogate both the disruptive and productive elements of friction, as Dutch consultants seek to realize the GGSW project in Jakarta. Examining the GGSW project as a liminal project that constitutes neither a success nor a failure, I advance theoretical understandings of policy immobility and failure. Chapter 4 examines the contentious politics of flood mitigation in Jakarta more broadly through an analysis of the environmentalism of Forum Kampung Kota, a network of activists, architects and academics. By tracing its changing tactics, from one centered on appeals to social and environmental justice to what I call ‘insurgent expertise’, this chapter enriches understandings of localized and differently positioned forms of environmental politics.