The COVID-19 pandemic is an unprecedented example of a crisis that greatly affected in the recent years many areas of people's lives and many aspects of the functioning of public institutions, as well as other commercial or social organisations. Disruptions accompanying the pandemic, such as the introduction of social isolation, changes to office and team working conditions, e.g., in projects, restrictions on the organisation of meetings or events involving a large number of people, as well as travel and, above all, border crossing restrictions, are just a few examples of the negative consequences of this crisis, which also affected cross-border integration and cooperation, as well as implementing cross-border projects.Despite measures taken over many years to strengthen the socio-economic convergence of the countries of the European Union, as well as the promotion of European Territorial Cooperation through, for example, INTERREG programmes, the outbreak of the pandemic quickly exposed the fragility of cross-border relations and even led to a resurgence of antagonism in such relations. In the face of the pandemic, the inadequacies of cross-border cooperation mechanisms and weaknesses in the management