The article deals with the experience of modeling (simulating) trade negotiations between the European Union (EU) and the Eurasian Economic Union (EAEU), conducted with the support of the J. Monnet project at the St. Petersburg University (SPbU). The authors ana-lyze views on the strengths and limitations of modeling, which exist in academic literature. SPbU’s experience of modeling the United Nations and the European Union is examined in the article. One of the distinguishing features of the EU-EAEU simulation was its high degree of complexity in thematic and institutional respects. The task of this model was to draw up a deep free trade agreement including not only trade in goods, but also related issues concern-ing services and capital movement. The organizers’ approach to elaborating the model’s rules is explained in detail and the preparation of specific game materials is recounted. A detailed rulebook contained featured recommendations on participant preparation and rules of behav-ior, and described procedural questions, the role of the simulated institutions and their inter-action during each of the game’s days, in accordance with the program. Also, a description of the simulation’s task, the game’s program and a list of literature useful for the participants were prepared; and trainings before the game were conducted. Furthermore, the article analyses the simulation’s course with regard to the entry list, logistics, problems that emerged during the negotiations, and participant successes and failures. The authors thought it fruitful to end the article not with a traditional conclusion, but with detailed methodological guidelines on or-ganizing and conducting models, based on the organizers’ experience of this game and taking into account practices existing in the world.