This study presents a preliminary comparison of networks of international collaboration and mobility. Using affiliation data from scientific publications, we analyse the structural differences in the two networks and the role of countries. The results show that researchers collaborate internationally to a much higher degree than they become internationally mobile. The number of countries involved in the networks is three times higher in collaboration than in mobility, and the average degree demonstrates that mobility networks form tight structures with fewer links than collaboration networks. The role of countries differs between the collaboration and mobility network, predominately reflecting income level. Limitations and future research are described to further understand the dynamics of collaboration and mobility networks.