In 2016, approximately 5 million students, about 2% of global tertiary enrolments, studied abroad. As globalisation of education advances, tertiary student mobility is an important channel through which highly skilled immigrants arrive and work in different nation states. Informed by the multidisciplinary internationalisation frameworks, this study applies social network analysis techniques to the UNESCO data, to explore and compare the international tertiary student mobility networks in 1999 and in 2012. Based on the network visualisation and statistical analyses, this research emphasises that an individual country's economic and political power and geographic location are increasingly significant in determining its position in the network. Compared to the 1999 networks, the developing world has played a more important role in the networks by becoming the new destination for study and sending out more students. Yet it is still the economically leading nations that serve as the critical bridges connecting the less developed countries/regions to the world. Underneath the seemingly balanced development, the developing nations might be in a more disadvantaged and peripheral position in 2012. This study is concluded with a discussion of the brain drain issue and how various nation states confront it in light of the global flow of tertiary students.