The rise of number of the actors of international relations and the subjective evolution of diplomacy caused development of external actions of sub-state actors. Several units, both in unitary and federal states, have in their competences the ability to provide actions, which could be classified as paradiplomacy. The aim of the article is to analyze sub-state diplomacy with the case study. The issue of defining actions taken abroad will be discussed. In order to illustrate the phenomenon, intensive external activity of one of the Spanish Autonomous Community – Catalonia will be presented. The case is particularly interesting, because of the wide range of competences and, consequently, the far-reaching institutionalization of the Catalan paradiplomacy and the usage of several instruments.