Coordination across healthcare system levels is a global imperative in order to assure efficient resource utilization and provide high-quality care. Whereas coordination in healthcare is a prominent research topic, this substantial body of research mainly concerns coordination across professional and organizational domains. Consequently, there is a dearth of empirical research aimed at delineating the determinants of coordination across healthcare system levels. Therefore, this paper describes and analyses the barriers and enablers of healthcare coordination across system levels. Individual interviews and focus group discussions, encompassing a total of 63 individuals, were conducted. The findings of the paper underscore that the barriers identified most often were of a structural or institutional character, whereas the enablers of the studied cross-level coordination were mostly relational. Therefore, we propose that future research should aim to further delineate the prerequisites for personal relationships to emerge, as well as how they may act as enablers of coordination across healthcare system levels.