The formation of social ties is a major factor in the international student experience (Ramsay et al. in High Educ 54(2):247-265, 2007), influencing student wellbeing and adjustment to the new academic and sociocultural environment (Ward et al. in The psychology of culture shock. Routledge, Hove, 2001). Although a significant body of research in the international student literature has explored the role of social ties in student adjustment (Maundeni in Race Ethn Educ 4(3):253-276, 2001), there is a lack of studies monitoring student sojourners' social ties longitudinally. This case study therefore sought to investigate the dynamics and functions of social ties by tracking a group of international students over one academic year. Semi-structured individual interviews were conducted at three time stages with 20 international postgraduate students at a single UK university. The aim was to replicate and extend the Functional Model of Friendship Networks (Bochner et al. in Int J Psychol 12(4):277-294, 1977) which suggests that student sojourners typically form three distinct social networks: a co-national network, a host national network, and a non-co-national international network. The data shows evidence for a lack of host contact, reveals complexities associated with co-national contact, and points to the dominance of highly supportive "international ties". Further longitudinal research is called for to further inform our understanding of international students' social contact patterns over time.