Flag state

By definition, a flag state is the state in which a vessel is registered. On the high seas, flag states hold sole jurisdiction over oceangoing vessels. In other words, ocean-going vessels on the high seas are required only to comply with globally agreed upon standards subject to enforcement by the flag state (Art. 217 UNCLOS).
However, the majority of ships above 1.000 GT are registered under flags of convenience.

The flag state is required to “ensure compliance with international rules and standards” for vessels registered to it and to provide for “effective enforcement” no matter where violations occur (Art. 217). UNCLOS requires a “genuine link” between the flag state and the registered shipping company; as such, inter-national legal scholars debate whether states with “open registries,” such as Panama and Liberia, are permitted under UNCLOS.

(ICCT, Air Pollution and GHG Emissions from Ocean-going Ships: Impacts, Mitigation Options and Opportunities for Managing Growth, March 2007)

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