Regulation & Compliance

Memorandum of UnderstandingMOU

A regional agreement coordinating port-state-control inspections — e.g. the Paris and Tokyo MOUs.

In the safety context, a Memorandum of Understanding (MOU) is a regional cooperation pact under which port states share inspection data and targeting, so a ship inspected in one member port informs targeting across the region. The Paris MOU (Europe and the North Atlantic) and Tokyo MOU (Asia-Pacific) are the most prominent.

MOUs publish performance lists — white, grey and black — ranking flag states by detention record, which feed directly into how ships are targeted for inspection and into third-party risk scoring.

On TheMaritime

Flag performance

Also known as: MOU, paris mou, tokyo mou.

Related terms

Port State ControlPSC

Inspection of foreign ships in national ports to verify they meet international safety and environmental standards.

Flag State

The country in which a ship is registered, whose laws she sails under and which is responsible for her regulatory oversight.

Plain-English reference definition — our own explanation of a standard shipping concept, not a licensed source or legal advice. See the full glossary or the broader maritime dictionary.

Last reviewed: June 2026.