Abstract This article highlights the contribution of East Central Europe to interwar internationalism by showing how solutions to regional challenges gave birth to the Union internationale des associations d'alpinisme (UIAA), a permanent international organisation for mountaineering. The territorial fragmentation caused by the dissolution of the Habsburg Empire required alpine clubs to lobby for the softening of new political borders while simultaneously contributing to state building efforts. Successful experiences with bilateral agreements in the Tatras and re-emerging Neo-Slavist ideas led to the founding of the Association of Slavic Tourist Organization in 1924, which in turn motivated the establishment of the UIAA. The leading figures in this process were alpinists with a distinct internationalist profile who navigated seamlessly between their role as agents of the state and private citizens.