Paradiplomacy, as a form of establishing foreign cooperation carried out by subregional entities, including regions and local governments, currently complements the official foreign policy and diplomacy conducted by nation states. One of the terms used to describe paradiplomacy is parallel diplomacy (i.e. parallel diplomacy), which perfectly reflects the role that this idea plays in relations between cities, regions of the European Union, cross-border cooperation and communities. Paradiplomacy is particularly common in the federal countries of Western Europe, South America South America, Asia and the United States of America. However, both within the EU and at national level, undertaking activities related to paradiplomacy at the administrative level requires legal regulations, from relevant statutes to concluded cooperation agreements. This also applies to Polish legislation. In this article, the authoruses an institutional and legal approach and empirical research to analyse the legal basis for paradiplomacy carried out by local government units (LGUs) in Poland. In addition to official records, he draws attention to informal and temporary activities and the effectiveness of the agreements concluded.