Flag-State Jurisdiction

Flag-state jurisdiction means that a merchant ship on the high seas is principally governed and supervised by the country whose flag it is entitled to fly. Under the United Nations Convention on the Law of the Sea (UNCLOS), ships generally fall under the exclusive jurisdiction of their flag state on the high seas, subject to exceptions recognised by the Convention or international treaties.

How a ship acquires its nationality

A ship's legal nationality connects it to a state responsible for regulating it; this need not be the country of its owner or crew.

• Under Article 91, each state determines the conditions for granting nationality to ships, registering them and permitting them to fly its flag; a genuine link must exist between the state and the ship.
• Under Article 92, a ship ordinarily sails under one state's flag and cannot change it during a voyage or port call except following a genuine transfer of ownership or change of registry.
• A ship using multiple flags according to convenience may be treated as a ship without nationality.

What the flag state must regulate

Exclusive jurisdiction carries duties, not merely protection against interference by other states. Article 94 requires the flag state to exercise effective jurisdiction and control over ships flying its flag in administrative, technical and social matters.

• The state must maintain a register of ships, subject to the Convention's exception for certain small vessels.
• It must take necessary safety measures concerning construction, equipment, seaworthiness, communications and collision prevention.
• It must ensure appropriate qualifications of masters and officers and sufficient, suitably qualified crews.

Why the flag matters for seafarers

The flag state's responsibilities extend to manning, labour conditions and crew training, taking account of applicable international instruments.

• A seafarer's nationality does not determine the ship's nationality: an Indian working aboard a foreign-flagged ship serves on a vessel subject to that flag state's jurisdiction.
• Another state with clear grounds to believe that proper jurisdiction and control have not been exercised may report the facts to the flag state, which must investigate and take appropriate remedial action.

Exceptions to exclusive jurisdiction

Flag-state authority does not make a vessel immune from every lawful intervention.

• Article 105 permits states to seize pirate ships on the high seas through authorised vessels or aircraft.
• Article 111 permits a coastal state to continue lawful hot pursuit onto the high seas when the Convention's conditions are satisfied.