Introduction. This article analyzes the professional self-determination process of international medical students during academic mobility. It demonstrates that a university's multicultural educational environment can act as both a source of barriers and a resource for professional development, but the mechanism of its mediating influence remains understudied. The objective is to use empirical data analysis to identify and characterize the mechanism of the mediating influence of a university's multicultural environment on the professional self-determination of international medical students. Materials and methods. An analysis of data collected in 2024–2025 among 32 international medical students from South Asian countries studying at Mari State University was conducted. The instruments included a questionnaire with open-ended and closed-ended questions, the Personality Self-Actualization Diagnostic Questionnaire (SAMOAL) developed by A. V. Lazukin, edited and adapted by N. F. Kalinа (scales: professional enthusiasm, striving for harmony, reflection, risk appetite) and the Subjective Well-Being Scale developed by French psychologists G. Perrudent-Badoux, M. Mendelsohn, and J. Chiche (adapted by M. V. Sokolova). Qualitative content analysis and quantitative analytical processing of the data were used. Results, discussion. A key resource was identified: absolute professional enthusiasm (100% of the sample). Significant barriers were identified: language (87. % of mentions), academic (68.8 %), and uncertainty about professional/career prospects after training (37.5 %). Low risk propensity (65.6 % of respondents) is interpreted as a rational adaptive strategy in the new institutional environment. The university's support system is highly valued by students (90.6 %), but its career guidance potential is not fully realized (only 46.9 % associate university activities with professional growth). A model is proposed in which a multicultural environment acts as a mediator between students' internal resources and external barriers. Conclusion. Professional self-determination in the context of academic mobility is a process of mediation. Mediation is an external influence that can act as a mechanism for professional self-determination. Targeted career guidance support from a university can transform a multicultural environment from an adaptation challenge into a resource for professional development. The development of pedagogical technologies for mediation support offers promising opportunities.