The Takeshima Island dispute between Japan and South Korea is a regional conflict that remains unresolved under international law to this day. This research aims to analyze the role of international law in conflict mitigation and identify the challenges in implementing dispute resolution mechanisms. Using a juridical-normative approach and a case study method, this research evaluates the effectiveness of international law in resolving territorial disputes based on the principles of uti possidetis juris, effective control, and the provisions of the United Nations Convention on the Law of the Sea (UNCLOS). The findings indicate that although international law offers various mechanisms for resolution such as negotiation, mediation, arbitration, and adjudication through the International Court of Justice (ICJ) political reluctance from the disputing parties serves as a major obstacle to the effective implementation of the law in such conflicts. South Korea exercises de facto control over Takeshima Island, while Japan continues to assert its claims based on historical documents and international legal principles. This ongoing tension negatively affects bilateral relations between the two countries and hampers efforts at regional cooperation. This study recommends a more intensive diplomatic approach, mediation, and the possibility of joint management as a temporary solution. Furthermore, reforms in the international legal system are necessary to enhance its effectiveness in handling complex disputes. Therefore, it is hoped that this research can contribute not only to the academic study of international law and the peaceful resolution of regional conflicts but also to the development and renewal of the international legal system itself.