This paper discusses how different forms of cross-border employee mobility all contribute to establishing social ties across different units of multinational enterprises (MNEs). Despite the growing recognition of the significance of employees' cross-unit social ties in MNEs for both individuals and the organisation, the mechanisms for creating such ties remain underspecified. We contribute to closing this gap by identifying the role that an array of forms of international mobility can play in promoting employees' (cross-unit) social ties inside MNEs. We draw upon empirical accounts of the job-related international mobility experiences of 72 high-skilled employees in three leading MNEs in the mobile telecommunications sector. Guided by a framework that utilizes some of the key concepts of the debate on social ties and social capital, we discuss traditional expatriation, short-term assignments, localised transfers and business travel in terms of the structure and strength of the cross-unit ties they engender, as well as their accessibility. We find (1) that it is not only traditional long-term assignments in the form of expatriation that enable individuals to create cross-unit social ties; and, (2) that different forms of international mobility promote cross-unit social ties in variable ways and to different extents.