Green buildings have recently become a key aspect of the construction field and bring along a renovation of the whole industry chain. Such changes introduce new challenges for all subjects involved, and designers are also affected by such issues, especially for the development of projects based on international green building standards. Within this scope, project management plays a key role in the optimization of the design phase. This research analyzes the design process of international projects from the project management perspective through a multiple case study approach, considering the sustainability-related tasks that negatively affect the project design development under two types of contractual approaches: Design-Build and Design-Bid-Build. It aims to identify whether the Design-Build or Design-Bid-Build process is the best solution for developing green building projects. Two case studies in Italy and two case studies in Spain are analyzed, and the effects of the project management issues are evaluated under three different points of view: Time, cost, and level of sustainability of the building. A poorly planned process for the achievement of the various green building features of the project can impact the project schedule and the budget, whereas, a poorly managed project could also negatively impact its green building features. Finally, this research also highlights the positive relationship between process integration and green building design development.