This paper examines how Serbia’s legal framework and procedures facilitate access to spa rehabilitation services for both domestic and foreign users, using Banja Koviljača Spa as a case study. While previous studies of Serbian spa tourism have focused on marketing and economic aspects, this study addresses the legal procedures and innovative solutions that enable international utilization of spa services. The analysis finds that existing laws and regulations pose no significant obstacles to foreign citizens seeking spa treatment in Serbia, with differences only in payment and insurance reimbursement processes. Banja Koviljača Spa—one of Serbia’s oldest and most renowned spas—is highlighted for its international cooperation with the Austrian social insurance system, an initiative introducing innovative rehabilitation models. Statistical data on spa usage are presented graphically, illustrating that foreign visitors currently comprise only about 5% of total spa patients. The paper discusses legal and practical challenges (such as capacity limitations and patients’ rights issues) and offers recommendations to improve legal frameworks and procedures. These include enhancing bilateral agreements, expanding infrastructure, and integrating wellness tourism trends into legal policy. The findings underscore the potential for Serbia’s spa sector, undersupportive legal procedures, to become a significant component of health tourism and attract more international clientele.