Freedom of Navigation and the Law of the Sea (UNCLOS)

The world's oceans do not belong to any one country. A single set of rules called the United Nations Convention on the Law of the Sea, or UNCLOS, tells every country what it can and cannot do at sea. It decides how far a country's power reaches into the ocean, and it protects the right of every ship, from any nation, to sail through most of the world's waters without being stopped or attacked. This right is called "freedom of navigation".

Why do we need it?

Imagine if every country could claim any part of the ocean it wanted, or stop any ship it disliked. Trade would break down, because almost 80% of world trade by volume moves by sea. Fishing, laying underwater cables, and even the internet (which runs through undersea cables) all depend on ships and countries agreeing on clear sea rules. UNCLOS gives every country, big or small, the same rulebook, so a small country's ships have the same rights as those of a big and powerful country.

Where did it come from?

Before UNCLOS, sea rules were mostly customs built up over centuries, and countries often disagreed on how far their waters extended. The United Nations held three big conferences on the Law of the Sea. The third one ran from 1973 to 1982 and produced UNCLOS, which was signed at Montego Bay, Jamaica, in 1982. It came into force in 1994, once enough countries had ratified it.

As of 2026, it has 171 parties (member countries plus the European Union). Notably, the United States has signed but never ratified UNCLOS, though it follows most of its rules as customary international law. Iran has signed but not ratified it either.

How does it divide the ocean?

UNCLOS creates zones moving out from a country's coastline, each with different rights:

• Territorial Sea (up to 12 nautical miles): The coastal country has almost full control, like on land, but foreign ships still get "innocent passage": the right to pass through peacefully without stopping.
• Contiguous Zone (12 to 24 nautical miles): The coastal country can enforce customs, tax, immigration and pollution laws here.
• Exclusive Economic Zone or EEZ (up to 200 nautical miles): The coastal country has the sole right to use resources like fish, oil and gas, but other countries can still sail and fly over it freely, and lay cables and pipelines.
• High Seas (beyond 200 nautical miles): These waters belong to no one. Every country's ships have full freedom of navigation, overflight, fishing and scientific research here, subject to UNCLOS rules.

Key straits and choke points

Some narrow sea passages, called straits, connect major seas and are used by a huge share of world shipping. The Strait of Hormuz (between Iran and Oman) and the Strait of Malacca (between Malaysia and Indonesia) are examples. Even where a strait passes through a country's territorial sea, UNCLOS gives all ships the right of "transit passage", a right that is even less restrictive than innocent passage, because these routes are so important for world trade.

Who enforces the rules?

UNCLOS set up institutions to apply and interpret the treaty:

• The International Tribunal for the Law of the Sea (ITLOS), based in Hamburg, Germany, settles disputes between countries about how UNCLOS should be read.
• The International Seabed Authority, based in Jamaica, manages mining of minerals from the seabed of the high seas, which belongs to all humankind under UNCLOS.
• The Commission on the Limits of the Continental Shelf helps countries fix the outer limit of their continental shelf beyond 200 nautical miles, where they can still claim seabed resources.

Piracy and attacks on ships

UNCLOS (Articles 100 to 107) requires all countries to cooperate to stop piracy on the high seas, and lets any country's warship seize a pirate ship anywhere outside another country's territorial waters. However, deliberate military-style attacks on ships by a state or an armed group, like torpedo or missile strikes, are treated differently: these raise issues of the law of war and state responsibility, not just anti-piracy law, and can be raised at the UN Security Council as a threat to international peace and security.

India's position

India ratified UNCLOS in 1995. When it did, India made a declaration that it does not agree that foreign countries can carry out military exercises or manoeuvres in its EEZ without its consent, a position not all countries share. India has used UNCLOS in international disputes, including the Bay of Bengal maritime boundary case with Bangladesh (decided in 2014) and the Enrica Lexie case with Italy over the shooting of Indian fishermen by Italian marines (an UNCLOS tribunal ruled on this in 2020).

India also supported the landmark 2016 UNCLOS tribunal ruling that rejected China's expansive claims in the South China Sea, calling for all countries to respect due regard for freedom of navigation.

Commonly confused concepts

• Territorial waters vs EEZ: In territorial waters, the coastal state has almost complete control, similar to land. In the EEZ, it only controls economic resources; navigation and overflight remain free for everyone.
• Innocent passage vs transit passage: Innocent passage (through territorial seas generally) can be temporarily suspended by the coastal state for security reasons in specified areas; transit passage (through straits used for international navigation) cannot be suspended.
• UNCLOS vs a country's domestic maritime law: UNCLOS is the international treaty that all parties must follow; each country then makes its own domestic laws (like India's Maritime Zones Act) to apply UNCLOS within its own boundaries.

Issues, criticism and the way forward

A newer international agreement, the "High Seas Treaty" or BBNJ Agreement (on Biodiversity Beyond National Jurisdiction), came into force on 17 January 2026 to protect marine life in the high seas, showing that UNCLOS is still being built upon. Critics point out that UNCLOS has weak tools against non-state actors, such as armed groups that attack ships, because the treaty was written mainly with pirates and states in mind, not modern proxy or missile attacks.

Some experts suggest that stronger international coordination through bodies like the International Maritime Organization, alongside UNCLOS, is the way to protect seafarers from attacks that fall outside classic "piracy".

Concepts to Know

• Nautical mile: A unit of distance used at sea, equal to about 1.85 kilometres, slightly longer than a normal (land) mile.
• Ratify: When a country's own government formally approves and commits to follow an international treaty it has signed.
• Continental shelf: The gently sloping seabed near a coastline, before the ocean floor drops sharply into the deep sea; countries can claim rights over its resources like oil and gas.
• State responsibility: The rule in international law that a country can be held responsible if its own actions, or actions it directs, cause harm to another country's people or property.