Why This Matters
In 1945, President Truman unilaterally claimed US jurisdiction over the natural resources of the continental shelf. Within a decade, coastal states were making overlapping claims to fishing zones, resource zones, and extended territorial seas. The resulting conflicts threatened to fragment the oceans into competing national domains. UNCLOS (1982) was the international community's answer: a comprehensive legal constitution for the oceans, covering navigation, resources, environment, and dispute settlement across all maritime zones. The OU examiner treats this chapter as one of the highest frequency topics in the entire paper, generating Part A definitions, Part B essays, and Part C problems in almost every paper from 2011 to 2022. Territorial waters alone produced three separate Part C problems across the PYQ analysis papers.
Chapter Overview
This chapter answers five questions:
- How did the law of the sea evolve? From freedom of the seas to UNCLOS.
- What are the maritime zones? Internal waters, territorial sea, contiguous zone, EEZ, continental shelf, high seas.
- What are the freedoms of the high seas? Their content and limits.
- What is the Common Heritage of Mankind? Its application to the deep seabed.
- What does UNCLOS provide? Its key provisions and significance.
Evolution of the Law of the Sea
The history of the law of the sea is the history of the tension between coastal state control and the freedom of navigation.
Hugo Grotius articulated the doctrine of mare liberum (the free sea) in 1609: the sea is res communis, belonging to all, incapable of appropriation by any state. Selden's counterargument, mare clausum (the closed sea), defended the right of coastal states to claim and control adjacent waters. The practical compromise that emerged was the cannon-shot rule: a coastal state controls the sea as far as its cannon can reach, approximately three nautical miles. This became the traditional territorial sea.
The inadequacy of three nautical miles became apparent as technology extended the reach of fishing and resource extraction. The League of Nations Codification Conference (1930) failed to agree a territorial sea limit. The Geneva Conventions of 1958 produced four instruments covering the territorial sea, the high seas, the continental shelf, and fishing, but left the breadth of the territorial sea unresolved. The Third UN Conference on the Law of the Sea (1973 to 1982) produced UNCLOS, which entered into force in 1994.
📋 What it addresses: The complete legal framework for all uses of the oceans and their resources. Covers maritime zones, navigation rights, resource extraction, environmental protection, scientific research, and dispute settlement.
📌 Key provisions: Territorial sea: 12 nautical miles. Contiguous zone: 24 nm. EEZ: 200 nm. Continental shelf: up to 350 nm. High seas freedoms. Common Heritage of Mankind for the Area. International Tribunal for the Law of the Sea (ITLOS) for disputes.
🎯 Significance: Called the "constitution of the oceans." Most comprehensive multilateral treaty on any single subject. 168 parties. Core provisions are customary international law binding all states.
Maritime Zones Under UNCLOS
UNCLOS divides ocean space into six zones, each with a different legal regime.
Internal Waters
Internal waters are the waters on the landward side of the baseline from which the territorial sea is measured. Ports, harbours, rivers, lakes, and enclosed bays are internal waters. The coastal state exercises full sovereignty over internal waters: foreign ships have no right of innocent passage. Entry to internal waters requires the coastal state's permission.
📋 Facts: Norway drew straight baselines connecting the outermost points of its deeply indented coastline and offshore islands (the skjaergaard), enclosing large waters as internal. British trawlers were arrested for fishing inside these lines, and the UK challenged the baseline method.
⚖️ Issue: Whether straight baselines across an indented coast were valid under international law.
🏛️ Held: Norway’s straight baselines were valid. Where a coast is deeply indented or fringed with islands, baselines need not follow the low-water mark; they may connect appropriate points, provided they follow the general direction of the coast.
🎯 Principle: The straight baseline method, now codified in Article 7 UNCLOS. Baselines determine where internal waters end and every other maritime zone begins.
🔗 Full case notes
Territorial Sea
The territorial sea extends up to 12 nautical miles from the baseline. The coastal state exercises sovereignty over the territorial sea, the airspace above it, and the seabed and subsoil beneath it. Sovereignty is subject to one critical limitation: the right of innocent passage.
Innocent passage is the right of foreign ships to pass continuously and expeditiously through the territorial sea without entering internal waters or calling at a port, provided the passage is not prejudicial to the peace, good order, or security of the coastal state. Passage must be continuous and expeditious: stopping or anchoring is permitted only in cases of distress or force majeure.
Article 19 UNCLOS defines what makes passage non-innocent: threatening force against the coastal state, weapons exercises, intelligence gathering, interference with communications, launching or landing aircraft or military devices, loading or unloading contraband, and serious pollution, among others.
📋 Facts: British warships passing through the Corfu Channel, an international strait within Albanian territorial waters, struck mines and suffered loss of life. Albania had not warned of the minefield.
⚖️ Issue: Whether warships had a right of passage through straits in peacetime, and whether Albania was responsible for the damage.
🏛️ Held: States in peacetime have a right to send warships through straits used for international navigation without prior authorisation, provided passage is innocent. Albania was responsible: every state has an obligation not to allow knowingly its territory to be used for acts contrary to the rights of other states.
🎯 Principle: Warship passage through international straits in peacetime, and the due-diligence duty to warn. The ICJ’s first contentious case and the foundation of transit rights later codified in UNCLOS.
🔗 Full case notes
Warships enjoy innocent passage through the territorial sea. The coastal state may require prior notification or authorisation for warships, though this is contested: UNCLOS does not expressly require it, and Western states treat prior notification as incompatible with the freedom of navigation.
I nnocent passage: right of all foreign ships including warships
T welve nautical miles: maximum breadth
F ull sovereignty: over water, airspace, seabed and subsoil
Contiguous Zone
The contiguous zone extends up to 24 nautical miles from the baseline. The coastal state may exercise control in the contiguous zone to prevent and punish infringement of its customs, fiscal, immigration, and sanitary laws within its territory or territorial sea. The coastal state has enforcement jurisdiction, not full sovereignty.
Exclusive Economic Zone
The EEZ extends up to 200 nautical miles from the baseline. The coastal state has sovereign rights over the EEZ for the purpose of exploring and exploiting, conserving and managing the natural resources of the waters, seabed, and subsoil. It also has jurisdiction over artificial islands and installations, marine scientific research, and the protection of the marine environment.
Other states retain important rights in the EEZ: freedom of navigation, overflight, and the laying of submarine cables and pipelines. The EEZ is neither territorial sea nor high seas: it is a sui generis zone with specific rights distributed between the coastal state and other states.
| Dimension | Territorial Sea | EEZ |
|---|---|---|
| Breadth | 12 nautical miles | 200 nautical miles |
| Coastal state rights | Full sovereignty (subject to innocent passage) | Sovereign rights over resources only |
| Navigation | Innocent passage only | Full freedom of navigation |
| Airspace | Coastal state sovereignty | Freedom of overflight |
| Legal character | Sovereign territory | Sui generis: resource zone |
Continental Shelf
The continental shelf is the natural prolongation of a coastal state's land territory to the outer edge of the continental margin, up to a maximum of 350 nautical miles from the baseline.
All coastal states have a continental shelf of at least 200 nautical miles regardless of the actual geological configuration. The coastal state exercises sovereign rights over the continental shelf for the purpose of exploring and exploiting its natural resources, principally oil, gas, and minerals. These rights are exclusive: no other state may exploit the shelf without the coastal state's consent.
The continental shelf regime is separate from the EEZ: a state can have continental shelf rights beyond 200 nm where the geological shelf extends further, but EEZ resource rights are capped at 200 nm.
📋 Facts: Germany, Denmark and the Netherlands disputed how to delimit their overlapping North Sea continental shelves. The equidistance method favoured the neighbours because Germany’s coast is concave.
⚖️ Issue: Whether the equidistance principle was a binding rule of customary international law for shelf delimitation.
🏛️ Held: It was not. Delimitation must be effected by agreement in accordance with equitable principles, taking account of all relevant circumstances, so as to leave each state the natural prolongation of its land territory.
🎯 Principle: Continental shelf rights exist ipso facto and ab initio as the natural prolongation of land territory; delimitation is governed by equitable principles, not mechanical equidistance.
🔗 Full case notes
High Seas
The high seas are all parts of the sea not included in the EEZ, territorial sea, internal waters, or the archipelagic waters of an archipelagic state. The high seas are open to all states. No state may purport to subject any part of the high seas to its sovereignty.
Freedoms of the High Seas
Article 87 UNCLOS: the high seas are open to all states and freedom of the high seas comprises the following freedoms.
The six freedoms of the high seas under UNCLOS are: freedom of navigation, freedom of overflight, freedom to lay submarine cables and pipelines, freedom to construct artificial islands and other installations, freedom of fishing, and freedom of scientific research.
These freedoms must be exercised with due regard for the interests of other states in exercising their own high seas freedoms and with due regard for the rights relating to activities in the Area.
The nationality principle governs vessels on the high seas. Every ship must fly the flag of a state. Ships on the high seas are subject exclusively to the jurisdiction of their flag state. No other state may interfere with a foreign ship on the high seas except in limited circumstances.
Exceptions to exclusive flag state jurisdiction on the high seas:
Piracy: Any state may seize a pirate ship or aircraft on the high seas and arrest the persons and seize the property on board. Piracy is defined as illegal acts of violence, detention, or depredation committed for private ends by the crew of a private ship against another ship on the high seas.
Slave trade: Every state must take effective measures to prevent and punish the carriage of slaves and may board a foreign ship suspected of engaging in the slave trade.
Hot pursuit: A coastal state may pursue a foreign vessel that has violated its laws from its own waters continuously onto the high seas, provided pursuit begins when the vessel is within the coastal state's zones and is not interrupted. Hot pursuit must cease when the vessel enters the territorial sea of another state.
Right of visit: A warship may board a foreign vessel on the high seas if there are reasonable grounds for suspecting that the vessel is engaged in piracy, the slave trade, unauthorised broadcasting, or is without nationality.
P iracy: universal jurisdiction, any state may seize
S lave trade: every state must take measures, may board
H ot pursuit: from coastal state's waters continuously to high seas
V isit: right of visit for suspected piracy, slave trade, broadcasting, statelessness
Common Heritage of Mankind
The deep seabed beyond national jurisdiction is designated the Area under UNCLOS. The Area and its resources are the common heritage of mankind.
The principle was first articulated by Ambassador Arvid Pardo of Malta in 1967. The deep seabed contains polymetallic nodules and other mineral resources of enormous economic value. Pardo argued these resources should not be appropriated by technologically advanced states capable of reaching them first. They belong to all humanity, including future generations and developing states without deep-sea mining technology.
The legal consequences of common heritage status under UNCLOS are: no state may claim or exercise sovereignty or sovereign rights over any part of the Area or its resources; all activities in the Area must be carried out for the benefit of mankind as a whole; the International Seabed Authority (ISA) organises and controls activities in the Area.
The International Seabed Authority (ISA) is the body through which states parties organise and control all mineral-related activities in the Area. The ISA licenses operations, collects fees, and distributes benefits to all states parties, with particular regard to developing states and landlocked states.
📋 What it addresses: The legal regime for the Area (deep seabed beyond national jurisdiction) and its resources as the Common Heritage of Mankind.
📌 Key provisions: ISA created. Enterprise (the ISA's operational arm) to mine the Area. Technology transfer to developing states. Production limitations. Revenue sharing.
🎯 Significance: Part XI as originally drafted was unacceptable to developed states (USA, UK, Germany). The 1994 Implementation Agreement modified it substantially, enabling near-universal ratification. The USA has still not ratified UNCLOS but treats most provisions as customary law.
| Dimension | Common Heritage of Mankind | Res Communis |
|---|---|---|
| Applies to | The Area (deep seabed beyond EEZ) | High seas, outer space |
| Exploitation | Only through ISA, benefits shared | Free use by all states |
| Sovereignty | Prohibited for all states | Prohibited for all states |
| Management | Collective through ISA | No collective management body |
| Benefit sharing | Mandatory, especially for developing states | None: first come, first served |
India and the Law of the Sea
India ratified UNCLOS in 1995. India's domestic framework is the Territorial Waters, Continental Shelf, Exclusive Economic Zone and Other Maritime Zones Act, 1976, supplemented by the Maritime Zones of India (Regulation of Fishing by Foreign Vessels) Act, 1981. India claims a 12 nm territorial sea, 24 nm contiguous zone, and 200 nm EEZ. India has an extended continental shelf claim beyond 200 nm in the Arabian Sea, Bay of Bengal, and around the Andaman and Nicobar Islands, submitted to the Commission on the Limits of the Continental Shelf (CLCS).
Common Confusions
The coastal state has sovereign rights over resources in the EEZ, not full sovereignty. Other states retain freedom of navigation, overflight, and laying of cables. The EEZ is a resource zone, not territorial sea. Full sovereignty exists only in the territorial sea (subject to innocent passage).
Innocent passage applies to all ships including warships. The controversy is whether warships require prior authorisation. UNCLOS does not require it. Western states assert warships enjoy the same innocent passage right without notification. Some states (India, China, Russia) require prior authorisation, a position contested by major naval powers.
Hot pursuit must begin when the foreign vessel is within the coastal state's internal waters, territorial sea, contiguous zone, or EEZ. It cannot begin from the high seas. If pursuit is interrupted, the right of hot pursuit ends.
Common Heritage of Mankind does not mean ownership by no one. It means ownership collectively by all of humanity, managed through the ISA for the benefit of all states particularly developing nations. Unilateral appropriation is prohibited; collective management through the ISA is mandatory.
Key Takeaways
UNCLOS 1982: constitution of the oceans, 168 parties, customary law status for core provisions.
Six zones: internal waters (full sovereignty, no innocent passage), territorial sea (12 nm, sovereignty subject to innocent passage), contiguous zone (24 nm, enforcement jurisdiction), EEZ (200 nm, sovereign rights over resources), continental shelf (up to 350 nm, resource rights), high seas (open to all, flag state jurisdiction).
Freedoms of high seas: six under Article 87. Flag state jurisdiction exclusive subject to PSHV exceptions.
Common Heritage of Mankind: the Area (deep seabed). ISA manages. No sovereignty. Benefit sharing. Contrasts with res communis of the high seas.
Memory Hooks: ITF: territorial sea rules PSHV: four exceptions to flag state jurisdiction Territorial sea vs EEZ table Common Heritage vs res communis table
Innocent Passage
Innocent passage is the right of foreign ships to navigate through the territorial sea of a coastal state continuously and expeditiously, without entering internal waters or stopping at a port, provided the passage is not prejudicial to the peace, good order, or security of the coastal state. It is recognised under Article 17 of UNCLOS (1982).
Passage ceases to be innocent if the ship engages in any of the activities listed in Article 19: threatening force against the coastal state, conducting weapons exercises, engaging in intelligence gathering, interfering with communications systems, polluting wilfully and seriously, or undertaking activities not related to passage. Stopping and anchoring are permitted only in cases of distress or force majeure.
Innocent passage applies to all ships including warships. The coastal state may not suspend innocent passage except temporarily in specified areas for reasons of security. The coastal state may not impose conditions on innocent passage that have the effect of denying or impairing the right.
Part A (6 marks)
Common Heritage of Mankind
The Common Heritage of Mankind is a principle of international law under which certain areas and resources are held in trust for all humanity and may not be appropriated by any single state. Under UNCLOS (1982), Part XI, the deep seabed beyond national jurisdiction, designated the Area, and its mineral resources are declared the common heritage of mankind.
The legal consequences are: no state may claim sovereignty over the Area or its resources; exploitation must be carried out only through or authorised by the International Seabed Authority (ISA); the benefits must be shared among all states, with particular attention to developing and landlocked states. The principle was first proposed by Ambassador Arvid Pardo of Malta in 1967 to prevent technologically advanced states from monopolising deep-sea mineral resources.
The principle contrasts with res communis, the status of the high seas: the high seas are freely usable by all states without collective management or benefit-sharing obligations. The Area goes further: it requires active collective management and equitable distribution of benefits.
Part B (15 marks)
Discuss the Legal Regime of the Seas under UNCLOS / Law of the Sea / Freedoms of the High Seas / Coastal State Jurisdiction
- UNCLOS 1982: comprehensive codification, in force 1994; "constitution of the oceans"
- Six maritime zones: Internal Waters, Territorial Sea (12 nm), Contiguous Zone (24 nm), EEZ (200 nm), Continental Shelf, High Seas
- Innocent passage: Article 17 UNCLOS; Article 19 lists 12 prohibited activities
- EEZ: sovereign rights for resource exploitation, jurisdiction over scientific research
- High seas freedoms (Article 87): Navigation, Overflight, Cables, Artificial islands, Fishing, Research
- Flag state jurisdiction: exclusive on high seas; four exceptions PSHV (Piracy, Slave trade, Hot pursuit, Visit)
- Common Heritage of Mankind: deep seabed ("the Area"), administered by ISA
- Hot pursuit: Article 111; must be continuous from coastal waters