The article explores the process behind the construction of the Chao Phraya Dam, the first World Bank-funded water infrastructure project in Thailand, developed during the 1950s. Employing Andrew Pickering's ‘dance of agency’ concept in examining the process of turning financial and technical assistance into a workable project, I argue that development infrastructure, like the Chao Phraya Dam, provides a space to explore the dialectic operations – accommodation and resistance – of agency and the unstable associations among diverse actors, expertise, institutions, and materials, as well as practices. Recounting the history of the dam in the making, I explore a series of entanglements through different dances of agency, namely initiation, assessment, mobilisation, negotiation, adjustment, confrontation, and settlement. Such a multiplicity of dances inside and in the making of infrastructure reflects the techno-political entanglement encompassing the manifold negotiation and adjustment of conflicting goals, interests, recognition, and cooperation among different agencies. The dam, often portrayed as an engineering achievement of the state, is in fact the result of unanticipated relations and the responses to the temporal emerging forms of practices.