The article discusses the determinants of local government contact networks within cross-border cooperation organizations (Euroregions). Relying on social capital theory, a combination of social network and qualitative analytical tools are applied on data from two Scandinavian and two East Central European cases. The analysis reveals that, even in favourable circumstances, contact networks are thin and Euroregions fail to develop into truly integrated political spaces. The analysis also shows that contact patterns on one side of the border, determined primarily by inter-municipal cooperation, will matter for how contact networks are formed across the border. The findings are important, as membership in a Euroregion is expected to foster cross-border political relationships that could have possible spillover effects in terms of encouraging policy cooperation outside the framework of the Euroregion, which in turn would enhance the likelihood of well-functioning cross-border governance spaces. © 2015 Taylor & Francis.