Ensuring the safety and security of shipping in Indonesian waters certainly cannot be separated from the role of the Marine and Coastal Guard Unit in carrying out its functions as a guard and enforcer of laws and regulations at sea and coast, which is the oldest organization in Indonesia that carries out guarding and law enforcement at sea. The history of the Marine and Coastal Guard Unit which began before Indonesia's independence. The problem in this research is how to regulate the legal authority of the Marine and Coast Guard to realize sovereignty, how to implement the authority and what factors are obstacles in exercising the authority to realize the sovereignty of the nation and state