Internal Waters

Introduction

Internal waters are the waters situated on the landward side of the baseline from which the breadth of the territorial sea is measured.

They are an important maritime zone under the United Nations Convention on the Law of the Sea (UNCLOS).

The coastal State generally exercises sovereignty over its internal waters in much the same way as over its land territory.

Internal waters may include:

• ports;
• certain bays;
• estuaries;
• waters enclosed by valid straight baselines;
• other waters lying landward of the baseline.

The key provision is:

Article 8 UNCLOS → Internal Waters

Definition of Internal Waters

UNCLOS does not provide a long independent definition of internal waters.

Instead, Article 8(1) establishes the basic rule:

Waters on the landward side of the baseline of the territorial sea form part of the internal waters of the State.

The concept therefore depends directly upon the baseline.

Basic Formula

Baseline

↓

Landward Side

↓

Internal Waters

↓

Coastal-State Sovereignty

Relationship with the Baseline

The baseline is crucial because it separates:

Internal Waters

from

Territorial Sea

The normal baseline is the low-water line along the coast, as recognised under Article 5.

Where UNCLOS permits the use of straight baselines under Article 7, waters enclosed landward of those baselines may become internal waters.

Legal Status of Internal Waters

The coastal State exercises sovereignty over its internal waters.

This sovereignty extends to:

• the water;
• the seabed;
• the subsoil;
• the airspace above the waters.

Therefore, internal waters are generally treated as being under the territorial sovereignty of the coastal State.

Internal Waters vs Territorial Sea

Although both are subject to coastal-State sovereignty, their legal regimes are different.

Internal Waters	Territorial Sea
Landward of baseline	Seaward of baseline
Coastal-State sovereignty	Coastal-State sovereignty
Generally no general right of innocent passage	Right of innocent passage
Article 8	Articles 2–32
Foreign ships generally require coastal-State permission to enter, subject to applicable rules/exceptions	Foreign ships have right of innocent passage

Right of Innocent Passage

The most important distinction is the right of innocent passage.

Under Article 17, ships of all States enjoy the right of innocent passage through the territorial sea.

There is generally no equivalent general right of innocent passage through internal waters.

Therefore:

Territorial Sea → Innocent Passage

Internal Waters → Generally no general right of passage

This is an important examination point.

Exception: Historic Rights of Passage

There is an important qualification.

Under Article 8(2), where the drawing of a straight baseline under Article 7 has the effect of enclosing as internal waters areas that had not previously been considered internal waters, a right of innocent passage may continue to exist in those waters.

Thus:

Newly Enclosed Internal Waters

↓

Pre-existing Innocent Passage

may continue under Article 8(2).

Ports

Ports are generally situated within the internal waters of a coastal State.

The coastal State exercises substantial control over:

• entry;
• port operations;
• customs;
• immigration;
• health and sanitary requirements;
• security.

A foreign merchant vessel does not generally have an unconditional international-law right to enter a State’s ports.

Port Entry

As a general principle, a coastal State may regulate access to its ports.

It may impose requirements concerning:

• customs;
• immigration;
• health;
• safety;
• security.

However, specific treaties and customary international law may impose additional obligations.

Foreign Merchant Ships

Foreign merchant ships entering internal waters are subject to the jurisdiction of the coastal State, subject to applicable international law.

The coastal State may exercise jurisdiction concerning matters occurring within its internal waters.

Jurisdiction Over Foreign Ships

The coastal State generally has broad jurisdiction over foreign vessels while they are in internal waters.

This differs from the more limited rules applicable to foreign ships merely exercising innocent passage through the territorial sea.

Internal Waters and Criminal Jurisdiction

The coastal State may exercise criminal jurisdiction over foreign ships in its internal waters.

The exact exercise of jurisdiction can depend upon:

• the nature of the offence;
• whether the offence affects the coastal State;
• applicable treaties;
• flag-State interests;
• customary international law.

Civil Jurisdiction

The coastal State may also exercise civil jurisdiction in appropriate cases concerning foreign ships and activities within its internal waters.

Again, applicable international and domestic law must be considered.

Warships

Warships raise a distinct issue.

Warships enjoy sovereign immunity under international law, and the coastal State’s ability to exercise jurisdiction over them differs from its jurisdiction over merchant vessels.

Under UNCLOS Article 32, subject to specified exceptions, nothing in UNCLOS affects the immunities of warships and other government ships operated for non-commercial purposes.

Sovereign Immunity of Warships

Therefore:

Merchant Ship

→ Generally subject to coastal-State jurisdiction

Warship

→ Sovereign immunity

This distinction is important in maritime law.

Bays

Certain bays may form part of internal waters.

However, not every indentation in a coastline qualifies as a legally recognised bay for purposes of enclosing internal waters.

UNCLOS provides specific rules concerning bays.

Legal Bays

Article 10 deals with bays.

The article establishes rules for determining when a coastal indentation can be treated as a bay for purposes of the Convention.

The general rules concerning bay closing lines involve geographical and dimensional requirements.

Bay Closing Line

Where a bay satisfies the requirements of Article 10, a closing line may be drawn across its entrance.

The waters landward of that closing line may constitute internal waters.

Historic Bays

UNCLOS recognises that certain historic bays may be governed by special rules.

The ordinary Article 10 rules do not necessarily determine the status of historic bays.

Historic title is therefore an important concept in determining the legal status of certain maritime areas.

Straight Baselines and Internal Waters

Straight baselines can significantly affect internal waters.

Under Article 7, where a State lawfully uses straight baselines, waters enclosed between the straight baseline and the coast may become internal waters.

However, the use of straight baselines is subject to UNCLOS conditions.

Limits on Straight Baselines

Straight baselines cannot be used arbitrarily.

They must:

• follow the general direction of the coast;
• satisfy the geographical conditions in Article 7;
• not be drawn to or from low-tide elevations except as permitted by UNCLOS;
• not result in cutting off another State’s territorial sea from the high seas or EEZ.

Rivers

Under Article 9, if a river flows directly into the sea, the baseline is generally a straight line across the mouth of the river between points on the low-water line of its banks.

The waters landward of that line are internal waters.

River Mouth Flowchart

River

↓

Flows Directly Into Sea

↓

Line Across Mouth

↓

Baseline

↓

Waters Landward

↓

Internal Waters

Ports and Permanent Harbour Works

Article 11 provides an important rule concerning ports.

For purposes of delimiting the territorial sea, permanent harbour works forming an integral part of the harbour system are regarded as part of the coast.

However, offshore installations and artificial islands are not treated as permanent harbour works.

This prevents artificial structures from automatically extending the normal maritime zones of a State.

Roads

Article 12 deals with roadsteads.

Roadsteads normally used for loading, unloading and anchoring ships, even if situated partly or wholly outside the outer limit of the territorial sea, may be included within the territorial sea.

However, this does not necessarily convert every roadstead into internal waters.

Low-Tide Elevations

Article 13 addresses low-tide elevations.

A low-tide elevation is a naturally formed area of land surrounded by and above water at low tide but submerged at high tide.

Its ability to serve as a baseline point depends upon its geographical position and the rules of Article 13.

Internal Waters and Islands

Where islands exist near a coast, the applicable baseline method becomes important.

Depending upon the circumstances, waters between:

• the mainland;
• islands;
• coastal features

may fall within different maritime regimes.

The legal classification must therefore be determined by applying UNCLOS baseline rules.

Internal Waters of Archipelagic States

Archipelagic States have a distinct regime under Part IV UNCLOS.

Waters enclosed by valid archipelagic baselines are known as:

Archipelagic Waters

These are not simply ordinary internal waters.

The archipelagic State exercises sovereignty over them, but that sovereignty is subject to special UNCLOS rights, including:

• innocent passage;
• archipelagic sea lanes passage.

Internal Waters vs Archipelagic Waters

Internal Waters	Archipelagic Waters
Landward of ordinary baseline	Enclosed by archipelagic baselines
Generally full sovereignty	Sovereignty subject to special UNCLOS regime
No general innocent passage	Innocent passage applies
Article 8	Part IV

Enclosed and Semi-Enclosed Seas

Part IX UNCLOS deals with enclosed and semi-enclosed seas.

These are maritime regions surrounded by two or more States and connected to another sea or ocean by a narrow outlet, or consisting entirely or primarily of territorial seas and EEZs of two or more coastal States.

States bordering such seas are encouraged to cooperate in:

• management of living resources;
• protection of the marine environment;
• scientific research;
• exploration.

These waters should not automatically be confused with internal waters.

Internal Waters and Sovereignty

The legal position can be represented as:

Internal Waters

↓

Territorial Sovereignty

↓

Domestic Law + International Law

The coastal State generally has the strongest territorial jurisdiction in this zone.

Internal Waters and Foreign Ships

A foreign vessel entering internal waters does not enjoy the same automatic navigation rights that it enjoys in the territorial sea.

This is because:

Internal Waters

→ Within coastal-State sovereignty

Territorial Sea

→ Sovereignty subject to innocent passage

Internal Waters and Maritime Navigation

International navigation is nevertheless facilitated through:

• treaties;
• port agreements;
• bilateral arrangements;
• customary rules;
• specific rights of access.

Therefore, the absence of a general innocent-passage right does not mean that foreign ships can never enter internal waters.

Internal Waters and International Straits

Some waters that might otherwise be under coastal-State control form part of straits used for international navigation.

The special UNCLOS regime of transit passage may then become relevant.

Thus, maritime classification must always be considered in its geographical context.

Internal Waters and Environmental Protection

The coastal State may regulate activities within internal waters to protect:

• marine ecosystems;
• water quality;
• fisheries;
• coastal habitats;
• public health.

UNCLOS Part XII establishes broader obligations concerning protection of the marine environment.

Internal Waters and Pollution

Because internal waters fall under coastal-State sovereignty, domestic regulation concerning pollution from ships and other activities can be particularly extensive, subject to applicable international obligations.

Internal Waters and Fisheries

The coastal State generally exercises control over fisheries in its internal waters.

Foreign fishing vessels ordinarily require permission under the coastal State’s domestic law and applicable international agreements.

Internal Waters and Customs

Customs jurisdiction is particularly important in internal waters and ports.

States may regulate:

• importation;
• exportation;
• prohibited goods;
• customs duties;
• inspection.

Internal Waters and Immigration

The coastal State may regulate entry and departure of persons through its ports.

Immigration controls are therefore a major aspect of port-State jurisdiction.

Internal Waters and Health

States may impose sanitary and health measures concerning ships entering their ports.

Such measures may be relevant to:

• infectious diseases;
• quarantine;
• public health;
• vessel sanitation.

Internal Waters and National Security

The coastal State exercises significant control over security within internal waters.

It may regulate:

• entry of vessels;
• military activities;
• port security;
• restricted areas;
• surveillance.

Internal Waters and International Law

Although internal waters are subject to strong coastal-State sovereignty, the State is not free from international law.

The coastal State must still comply with:

• treaty obligations;
• customary international law;
• applicable human-rights obligations;
• rules concerning diplomatic and sovereign immunity;
• other international obligations.

Internal Waters and State Responsibility

If a coastal State acts unlawfully within its internal waters, it may incur international responsibility.

Territorial sovereignty does not provide immunity from international obligations.

Important UNCLOS Provisions

Remember:

Article 5 → Normal Baseline

Article 7 → Straight Baselines

Article 8 → Internal Waters

Article 9 → Mouths of Rivers

Article 10 → Bays

Article 11 → Ports

Article 12 → Roadsteads

Article 13 → Low-Tide Elevations

Article 14 → Combination of Methods

Article 15 → Territorial Sea Delimitation

Article 17 → Right of Innocent Passage

Article 18 → Meaning of Passage

Article 19 → Meaning of Innocent Passage

Article 20 → Submarines

Article 32 → Immunities of Warships

Internal Waters vs Other Maritime Zones

Zone	Extent / Basis	Main Legal Character
Internal Waters	Landward of baseline	Coastal-State sovereignty
Territorial Sea	Up to 12 nm	Sovereignty + innocent passage
Contiguous Zone	Up to 24 nm	Limited enforcement jurisdiction
EEZ	Up to 200 nm	Sovereign rights + specified jurisdiction
Continental Shelf	Seabed/subsoil, potentially beyond 200 nm	Resource rights
High Seas	Beyond national maritime zones	Freedoms; no sovereignty

Internal Waters vs Territorial Sea vs EEZ

Internal Waters

Sovereignty

↓

Generally no general right of innocent passage

Territorial Sea

Sovereignty

↓

Innocent Passage

EEZ

Sovereign Rights

↓

Navigation freedoms retained by other States

Important Case: S.S. Lotus

The S.S. Lotus (France v Turkey) case before the Permanent Court of International Justice concerned jurisdiction over a collision on the high seas.

Although it was not primarily an internal-waters case, it is important for understanding the broader distinction between:

• coastal-State jurisdiction;
• flag-State jurisdiction;
• high-seas jurisdiction.

Important Case: Anglo-Norwegian Fisheries

The Fisheries Case (United Kingdom v Norway) is important for the law concerning straight baselines.

The ICJ considered Norway’s method of drawing straight baselines along its deeply indented coast and island-fringed coastline.

The case is particularly relevant when studying:

• baselines;
• coastal geography;
• territorial waters.

Internal Waters Flowchart

Coast

↓

Baseline Established

↓

Landward Side

↓

Internal Waters

↓

Coastal-State Sovereignty

↓

Domestic Jurisdiction

Baseline to Maritime Zones

Coast

↓

Baseline

↓

Internal Waters

↓

12 nm → Territorial Sea

↓

24 nm → Contiguous Zone

↓

200 nm → EEZ

Quick Revision

• Internal waters are waters on the landward side of the baseline.
• Main provision → Article 8 UNCLOS.
• Normal baseline → Article 5.
• Straight baselines → Article 7.
• Internal waters are generally subject to coastal-State sovereignty.
• Sovereignty extends to:
  • water;
  • seabed;
  • subsoil;
  • airspace above.
• Ports generally form part of internal waters.
• Coastal State has extensive jurisdiction over internal waters.
• Foreign ships do not generally enjoy a general right of innocent passage through internal waters.
• Territorial sea → innocent passage.
• Article 8(2) preserves a possible innocent-passage right where straight baselines newly enclose waters that were not previously internal waters.
• Article 9 → River mouths.
• Article 10 → Bays.
• Article 11 → Ports.
• Article 12 → Roadsteads.
• Article 13 → Low-tide elevations.
• Warships enjoy applicable sovereign immunity.
• Article 32 → Warship immunity.
• Internal waters are different from territorial sea.
• Internal waters are different from archipelagic waters.
• Internal waters are different from EEZ.
• Historic bays may be governed by special rules.
• Straight baselines can affect the extent of internal waters.
• The coastal State may regulate:
  • customs;
  • immigration;
  • health;
  • fisheries;
  • security;
  • pollution.
• Coastal-State sovereignty remains subject to international law.
• Fisheries Case (UK v Norway) is important for straight baselines.
• S.S. Lotus is important for broader maritime jurisdiction principles.

One-Line Memory Trick

Internal Waters

“Landward = Internal”

If it is:

Landward of the Baseline

→ Internal Waters

Core Rule

Internal Waters → Sovereignty

Territorial Sea → Sovereignty + Innocent Passage

EEZ → Sovereign Rights

Important Articles

5 → Baseline

7 → Straight Baselines

8 → Internal Waters

9 → River Mouths

10 → Bays

11 → Ports

12 → Roadsteads

13 → Low-Tide Elevations

17 → Innocent Passage

32 → Warship Immunity

Conclusion

Internal waters constitute the maritime area lying on the landward side of the baseline. Under Article 8 of UNCLOS, they form part of the coastal State’s territory and are generally subject to its full territorial sovereignty.

The concept is closely connected with the law of baselines. The normal baseline under Article 5 is the low-water line, while Article 7 permits straight baselines in specified geographical circumstances. These rules can determine which waters fall within the internal waters of a State.

The most important distinction is between internal waters and the territorial sea. Although the coastal State exercises sovereignty over both, foreign ships generally enjoy a right of innocent passage through the territorial sea, whereas there is no equivalent general right of innocent passage through internal waters. Article 8(2), however, preserves certain passage rights where straight baselines newly enclose waters that were not previously internal waters.

Ports, certain bays, river mouths and waters enclosed by valid straight baselines may form part of internal waters. The coastal State consequently exercises extensive authority concerning navigation, customs, immigration, health, fisheries, security and environmental regulation.

At the same time, sovereignty over internal waters is not unlimited. The coastal State remains bound by its obligations under international treaties and customary international law, and special rules concerning warships, historic bays and international navigation may modify the ordinary position.

For examination purposes, remember:

Baseline → Landward Side → Internal Waters → Sovereignty

and:

Internal Waters ≠ Territorial Sea

Internal Waters → Generally no general innocent passage

Territorial Sea → Innocent Passage