Purpose. The aim of the article is to provide a scientific substantiation of the essence of the concept of "public diplomacy" and its role within the context of global geopolitical and geoeconomic fragmentation, considering current and potential global challenges and threats; to outline the vectors and instruments of Ukraine’s public diplomacy. Methodology of research. A combination of general scientific and specialized methods was employed in the research process. This included induction and deduction during the information collection, systematization, and trend identification phases within global geopolitical and geoeconomic fragmentation. Analysis and synthesis were utilized to pinpoint key trends in international relations and propose strategies to enhance the effectiveness of public diplomacy. Abstract and logical methods were applied to consolidate information from various sources, construct a comprehensive understanding of the research problem, and formulate theoretical conclusions and generalizations. The method of comparativistics was used to analyse the primary vectors of global geopolitical and geoeconomic fragmentation, discern local and regional characteristics, and establish global patterns and cause-and-effect relationships. Additionally, graphic methods were utilized to visually represent research findings. Findings. Theoretical foundations and essential characteristics of public diplomacy were systematized. An analysis of the level of geopolitical and geoeconomic fragmentation was conducted, determined through practical analysis of expert opinions using the Delphi method. It has been revealed that heightened geopolitical risk correlates with diminished levels of investment, stock prices, and employment, and is also associated with an increased likelihood of economic disasters, along with heightened risks of global economic collapse and geo-economic fragmentation. The geopolitical determinants that have fundamentally reshaped the role of public diplomacy in the global context from the late 20th century until the present were examined,, and contemporary vectors of geopolitical and geoeconomic fragmentation in the world were identified. Originality. The essence of public diplomacy is scientifically substantiated. In particular, it is argued that public diplomacy is a complex and multifaceted concept, grounded in the idea of "soft power" as an integral component of a state’s strategic communication policy within the framework of international relations. Essential characteristics of public diplomacy are summarized, and its role in the context of modern geopolitical and geoeconomic fragmentation of the world is substantiated, particularly concerning the resolution of interstate conflicts of military, economic, and hybrid natures. Based on empirical analysis, it has been demonstrated that the current geoeconomic and geopolitical fragmentation of the world revolves around the following three vectors of international problems: the Russian-Ukrainian war, tensions between China and Taiwan, and the geoeconomic and geopolitical competition for the resources of the African continent. The growing role of Ukraine in the future geopolitical structure of the world and the creation of a new concept of Europe’s collective security through the formation of regional military-political and security alliances were substantiated. Practical value. The conclusions and proposals substantiated by the research findings can be applied to determine the strategic directions of Ukraine’s public diplomacy, thereby enhancing the efficacy of its tools within the context of existing and potential global challenges and threats. Key words: international relations, foreign policy, global risks, international conflicts, geopolitical confrontation, geoeconomic fragmentation, public diplomacy, tools of public diplomacy, strategic communications, soft power, index of geopolitical risks