The paper seeks to contribute to mapping current (potential) transformations in cross-border institutional activity and understanding the mechanisms of the changed geo-political environment taking place in Europe since 2015. It does so through a study of how institutionalized cross-border cooperation institutions, referred to in the paper as Euroregions, responded to re-bordering policies at internal (Schengen) borders. The number of Euroregions has increased significantly since the early 1990s and many of them have benefited from EU technical and financial support. This has been done under the presumption that these institutions will promote local cross-border flows of goods, services and people, making them laboratories of European integration at a local, smaller, scale. The metaphor of “laboratory”, which has often been used in research on borderlands and these institutions, has regained analytical purchase since 2015, when countries that are parties to the Schengen agreement increasingly started to reinstate internal border controls following heightened public attention to the number of refugees reaching and crossing Europe. This practice became five times as frequent in the 2015-2019 period, compared to the preceding five years according to data from the European Commission. This was followed by the unprecedented border closures induced by the Covid-19 pandemic. The paper conducts a document analysis of written reports and statements by Euroregions situated at two internal borders with a high degree of integration (Austria/Germany and Denmark/Sweden), in order to map what these institutions said (or did not say) when borders reappeared in their midst, and whether there was convergence around resistance, or tensions leading to quiet compliance? © 2021 European Consortium for Political Research.