Throughout its history, Ukrainian diplomacy has gone through different periods; the legacy of the events of the 20th century is of practical importance for modern Ukraine, the establishment of its statehood, and recognition as an equal subject in the global international arena. Using the achievements of predecessors in this area, considering past mistakes and miscalculations, it is now possible to strengthen the state's diplomatic activity on a democratic basis with specific national characteristics. The purpose of the study is to provide practical recommendations for the development and strengthening of Ukrainian diplomacy at the present stage by identifying theoretical and conceptual approaches to the ways, methods, and means of developing the diplomatic service of the state in different historical periods of the 20th and 21st centuries. The comparative historical method was used to prepare this work, which, through comparison and analysis, identified the key points, features, nature of the interaction, and specifics of the process of diplomatic activity of the Ukrainian state in the 20th – early 21st centuries. The originality and identity of the diplomatic service of the Ukrainian state and the strengths and weaknesses of foreign policy at different stages of the country's historical development were identified. The author outlines the most significant international achievements of the first independent Ukrainian Republic and identifies the key features and basic features that determined the future development of the country's domestic diplomatic corps. The most optimal mechanisms, instruments, and means of Ukraine's international activity to implement them in the modern practice of international relations were indicated. Considering the priority areas for bilateral and multilateral diplomatic cooperation, the author proposes variant solutions and possible scenarios for further transformation of the country's foreign policy course regarding specific vectors of cooperation. The results and conclusions of the work can be used as a framework for future practical research, in particular, in the development and implementation of new systems and mechanisms of the best international practices in the field of diplomatic service in the national foreign policy