Nationality of Ships

A ship’s nationality is conferred by the flag state under UNCLOS Article 91, which lets each state set its own registration conditions subject to the genuine-link requirement. Nationality determines which state’s law governs the ship as a floating piece of that state’s jurisdiction, who may exercise diplomatic protection over it, and which navy may board it on the high seas. A ship sailing under two or more flags of convenience, switching as suits it, may be treated as a ship without nationality under Article 92.