Multi- and plurilateral treaties enable and shape global sports by creating a legal, operational, and ethical framework that facilitates international cooperation, standardizes practices, and promotes fairness, integrity, and inclusiveness in sports. These treaties not only govern the technical aspects of sports but also contribute to broader social goals, such as human rights protection and environmental sustainability. This chapter examines three key roles of treaties to global sports: (1) harmonizing the rules of sports at the global level by setting common standards for competition, athlete conduct, doping regulations; (2) combatting corruption and fraud; (3) protecting athletes’ rights and promoting gender equality in global sports. Specifically, this article also take a point of view from plurilateral sports agreements among ASEAN countries promoting sports as a diplomatic tool to ease tensions and foster better relations between member states. The SEA Games, in particular, is an important vehicle for diplomacy, with member countries using the event to build mutual understanding and resolve political differences through soft power.