The inter-firm collaboration networks created by international construction contractors have greatly influenced not only project success, but also potential business opportunities. However, despite the significance of collaboration, current research about organizational networks focuses on project teams and the limited collaboration among participants in a single project. This study consists of a preliminary investigation of 1) how the structure and properties of inter-firm collaborations change over time and 2) which network properties have the greatest effects on the business performance of member firms. To this end, this study analyzes cases of collaboration between Korean construction firms involved in international projects over the last decade. Periodic networks were developed and a longitudinal analysis was conducted to find empirical evidence. The results show that as the size of inter-firm networks increases, the networks become denser and center around the most densed large group. The results also indicate that the centrality of individual firms has a positive correlation with future contract revenues, especially considering the two-year lag.