The paper allows countries sharing transboundary river basins and RBOs to better understand the climate financing landscape and how to prepare bankable projects. It explains the importance of taking a transboundary approach to address climate change and discusses the challenges and opportunities for RBOs confronted with the task of carrying out their mandate in the increasing complexities of a changing climate (chapter 1). Chapter 2 describes financing opportunities available to countries sharing transboundary river basins to address climate adaptation, including global funds, private sector finance, and national and concessional finance with attention to how these sources can work together. Chapter 3 explores the requirements for developing bankable project proposals that are thus more likely to receive the required financing. The paper focuses on the bankability of transboundary river basin projects, with detailed options and recommendations that countries and RBOs may consider as they advance on their adaptation planning and implementation.