Flag State Enforcement

Flag-state enforcement is the duty and primary competence of the state whose flag a ship flies to exercise jurisdiction and control over it in administrative, technical, and social matters. UNCLOS Article 94 requires every state to maintain a register, exercise jurisdiction under its internal law over each ship and its master, officers, and crew, and ensure safety at sea covering construction, manning, and signals. On the high seas a ship is generally subject to the exclusive jurisdiction of its flag state under Article 92, which is why port-state control developed to address flag-state default.