This paper studies (trans)national social capital gained through an international study experience in Belgium. Drawing upon a multi-method alumni study, we explore different types of (inter)national networks of male and female graduates, the extent to which different networks remained after graduation as well as effects on personal and professional development and organizational performance. Findings show that graduates have particularly gained networks with non-co-nationals which evolve from bridging relations at the outset to bonding relations while particularly networks with the host population remain limited. After returning home, bonding social interaction relations remain most important, irrespective of the nationality of the graduates, whereas information sharing and collaboration networks survive better among co-nationals, particularly when these are triggered through national alumni chapters. Our study finds network effects on individual's intercultural skills, knowledge and attitudes, their professional career and organizational performance, with intercultural gains being particularly high for networks with non-co-nationals from other continents.