What are International Waters?

International waters sit outside a country's territorial sea, but the legal position changes across the contiguous zone, Exclusive Economic Zone and high seas. These maritime zones affect navigation, flag-state jurisdiction and some aspects of yacht ownership, including offshore yacht sales and transfers. This guide explains the key boundaries, the laws that apply, and what yacht buyers and owners need to know.

International waters is a broad term often used for areas of sea beyond a country's territorial waters. Under the United Nations Convention on the Law of the Sea (UNCLOS), however, the ocean is split into several legal zones, including the territorial sea, contiguous zone, Exclusive Economic Zone (EEZ) and high seas.

A coastal state's territorial sea can extend up to 12 nautical miles (22.2km) from its baseline, while its EEZ can extend as far as 200 nautical miles (370.4km). The high seas begin beyond waters covered by an EEZ, territorial sea, internal waters or archipelagic waters.

A yacht can change ownership while it is offshore, and the vessel's location at the point of delivery can matter for the sale. Buyers and sellers may therefore need clear evidence of where the yacht was when ownership changed, as well as the usual sale, registry and title documents.

The United Nations Convention on the Law of the Sea

The United Nations Convention on the Law of the Sea (UNCLOS) sets the main legal framework for the world's oceans. It defines maritime zones, sets out navigation rights and duties, and establishes the rights and jurisdiction of coastal and flag states.

For yacht owners and operators, UNCLOS helps determine which state has rights or jurisdiction in different parts of the sea and what freedoms apply to navigation. It also provides the legal basis for the territorial sea, contiguous zone, Exclusive Economic Zone and high seas covered in this guide.

The full text of UNCLOS is available from the United Nations.

The law that applies to a yacht depends partly on where the vessel is. Within a country's territorial sea, the coastal state has sovereignty, although foreign vessels have rights such as innocent passage under UNCLOS.

Within the contiguous zone, which can extend up to 24 nautical miles from the baseline, the coastal state has limited powers linked to customs, fiscal, immigration and sanitary laws.

Farther offshore, a yacht may still be inside an Exclusive Economic Zone. A coastal state does not have the same sovereignty there as it does in territorial waters, but it retains specific rights and jurisdiction over matters such as natural resources, marine research and environmental protection. Other states retain freedoms that include navigation.

On the high seas, yachts remain tied to their flag state. UNCLOS states that ships normally sail under one flag and are subject to that state's jurisdiction, subject to specific exceptions under international law.

On a crewed yacht, the captain and senior crew will usually handle voyage planning, vessel documents, customs requirements and the practical checks needed before an international passage. Owners and yacht managers still need to make sure the yacht has the right registration, insurance and legal setup for its flag, use and destination.

Crossing into international waters does not remove a yacht from flag-state rules or the laws that apply when it enters another country's waters or ports. Registration papers, safety requirements, crew documents, radio licences, insurance certificates and customs paperwork may all need to be checked before departure.

The exact requirements depend on the yacht's flag, size, use and destination. Commercial and charter yachts can also fall under international rules such as the International Safety Management Code and Maritime Labour Convention where applicable.

The captain, yacht manager or owner should check current requirements with the yacht's flag registry and the relevant authorities for each country on the planned route.

A yacht does not enter a law-free area when it leaves territorial waters. Its flag state continues to have jurisdiction over the vessel in many matters, while coastal states retain specific rights in the contiguous zone and Exclusive Economic Zone.

The documents a yacht needs depend on its flag, size, use and destination. Registration papers, crew certificates, radio licences, insurance documents and customs records may all be relevant, while commercial and charter yachts can face further requirements.

Legal consequences also depend on where an incident takes place and what law applies. A collision on the high seas, a customs offence in the contiguous zone and an unauthorised commercial operation in territorial waters are not dealt with under one single set of rules.

For that reason, owners, captains and yacht managers should check flag-state requirements as well as the laws of the countries and ports on the planned route.

International waters sit outside a country's territorial sea, but the legal position changes across the contiguous zone, Exclusive Economic Zone and high seas. Under UNCLOS, the territorial sea can extend up to 12 nautical miles from a state's baseline, the contiguous zone up to 24 nautical miles, and the EEZ up to 200 nautical miles. The high seas lie beyond the maritime zones covered by national sovereignty or specific coastal-state rights.

For yacht owners, captains and managers, crossing beyond territorial waters does not mean that national rules stop applying. Flag-state law remains important, while coastal states retain defined rights within the contiguous zone and EEZ.

International waters can also matter during yacht sales and offshore transfers because the yacht's location at the point of delivery may affect tax, customs, registration or title requirements. Those issues depend on the countries involved, the yacht's status and the terms of the sale, so they need to be checked case by case.