International collaboration in research activities has been highlighted because it offers higher productivity and has a greater impact than non-international collaboration. Given the importance of international collaboration, researchers make strategic decisions on their collaboration modes in the light of their environments and the expected trade-offs, since long-distance research collaboration entails both costs and benefits. By using national data at the project level, this paper examines the possible factors in international collaboration in various research areas, mainly focusing on research activities by universities. Our empirical results suggest that substantial financial and attentional resources, academic excellence, individual motivation, and active informal communication play significant roles in accomplishing international collaboration. Additionally, this paper refines the understanding of the role of communication and policy in ensuring the most effective use of research resources, helping research managers to promote collaboration in an appropriate decision-making context.