The transition from projects to operations requires a spanning from more temporary, goal-oriented, and evolving organizational forms to more permanent, routine, and ongoing organizational forms. A question of practical and theoretical significance is how to organize the transition to operations in large inter-organizational projects. To answer this question, we conducted a longitudinal case study of Beijing Daxing International Airport, which is the largest transportation hub in China to date, and provides rich evidence for successfully managing the transition to operations. By analyzing the organizational design strategy, structures, processes, and management of people in the transition, we provide a synthetic framework for designing the transition to operations in large inter-organizational projects. The framework provides a set of considerations to design organizational boundaries that build connections, emphasize coordination, and achieve continuity between projects and operations. This study contributes to the nexus of operations management and project management and the organizational design of large inter-organizational projects.