Territorial sea

What Is Territorial Sea?

The territorial sea is a belt of coastal waters extending up to 12 nautical miles (about 22 kilometers or 14 miles) from a nation's baseline. It falls under the complete sovereignty of the coastal state, encompassing the airspace above, the seabed below, and the subsoil. Within this zone, the coastal state has the right to enforce its laws and regulations, similar to its land territory. However, this sovereignty is subject to the international law principle of "innocent passage" for foreign vessels, meaning ships of other nations are generally permitted to transit peacefully through the territorial sea, provided they do not prejudice the coastal state's peace, good order, or security.²⁸,²⁷

This concept is a fundamental component of international law and maritime boundaries, primarily governed by the United Nations Convention on the Law of the Sea (UNCLOS). While not a direct financial term, the territorial sea plays a crucial role in resource management, national security, and international trade, all of which have significant economic implications for a coastal state.

History and Origin

The concept of states asserting jurisdiction over adjacent waters emerged in the 16th and 17th centuries, evolving from earlier notions of freedom of the seas. Initially, the extent of a nation's control was often tied to the "cannon-shot rule," which suggested that a state's dominion extended as far as a cannonball could be fired from its shore—typically around three nautical miles., ²⁶T²⁵his rule was popularized by jurists like Cornelius van Bynkershoek in the early 18th century.,
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23However, as naval technology advanced and global trade expanded, the traditional three-mile limit became increasingly insufficient for coastal states to protect their interests and manage marine resources. T²²he need for a universally recognized framework led to a series of international conferences. The United States, for instance, adopted the three-mile limit for neutrality purposes in 1793. E²¹fforts to codify maritime law gained momentum in the 20th century. While the 1958 Geneva Conventions on the Law of the Sea addressed several aspects, a definitive agreement on the breadth of the territorial sea remained elusive.,
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19The modern definition and scope of the territorial sea were primarily codified by the United Nations Convention on the Law of the Sea (UNCLOS), adopted in 1982. This comprehensive treaty, which entered into force in 1994, established the 12-nautical-mile limit as the widely accepted standard for the breadth of the territorial sea, reflecting a balance between a coastal state's sovereignty and the freedom of navigation.,,^18
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16## Key Takeaways

• The territorial sea is a 12-nautical-mile belt of ocean adjacent to a coastal state's land territory.
• A coastal state exercises full jurisdiction over its territorial sea, including the airspace and seabed.
• Foreign vessels generally have a right of "innocent passage" through the territorial sea, provided their transit is peaceful and does not threaten the coastal state's security.
• The concept evolved from the historical "cannon-shot rule" and was codified by the 1982 UN Convention on the Law of the Sea (UNCLOS).
• It is vital for national security, environmental protection, and the regulation of economic activity within the coastal zone.

Interpreting the Territorial Sea

The territorial sea represents the immediate extension of a state's land territory into the sea. Its interpretation is straightforward: within this zone, the coastal state holds sovereign rights and can enforce its laws without significant external interference, subject only to the right of innocent passage. This means the state can regulate activities such as fishing, pollution, customs, and security. For instance, any unauthorized exploration or exploitation of resources within the territorial sea would be a violation of the coastal state's sovereignty.

¹⁵The determination of the baseline from which the breadth of the territorial sea is measured is crucial for its precise interpretation. This is typically the low-water line along the coast as marked on official charts. In complex coastlines with deep indentations or fringing islands, straight baselines connecting appropriate points can be used.

Hypothetical Example

Imagine the fictional island nation of "Atlantica." Atlantica's coastal state authorities define its baseline along its low-water mark. From this baseline, Atlantica's territorial sea extends 12 nautical miles into the ocean.

If a foreign research vessel, the "Ocean Explorer," wishes to conduct marine scientific research within 5 nautical miles of Atlantica's coast, it must first obtain permission from the Atlantican government. This is because the intended research falls within Atlantica's territorial sea, where Atlantica exercises full sovereignty over marine resources and scientific activities. If the "Ocean Explorer" were merely passing through this zone on its way to international waters, it would generally be allowed to do so under the right of innocent passage, provided it navigated peacefully and without engaging in activities detrimental to Atlantica's security or interests. However, deviating from a continuous and expeditious passage or conducting unauthorized research would constitute a violation of Atlantica's sovereign rights within its territorial sea.

Practical Applications

The territorial sea has several critical practical applications in the real world:

• National Security and Defense: It provides a buffer zone where a coastal state can enforce its customs, fiscal, immigration, and sanitary laws, and take measures to protect its security against threats emanating from the sea. Military vessels of other nations, while enjoying innocent passage, are subject to specific rules and can be required to leave if their passage is not innocent.
  *¹⁴ Resource Exploitation and Conservation: States have exclusive rights to explore and exploit all natural resources within their territorial sea, including fisheries, minerals, and oil and gas. This allows for controlled resource management and benefits the local economic activity.
  *¹³ Environmental Protection: Coastal states can enact and enforce laws to prevent pollution within their territorial waters, protecting their marine environment from harmful discharges from vessels.
• Regulation of Navigation: While innocent passage is permitted, coastal states can establish sea lanes and traffic separation schemes to enhance the safety of maritime traffic. The International Maritime Organization (IMO), a specialized agency of the United Nations, plays a key role in developing a global regulatory framework for shipping, including safety and environmental standards that apply in and beyond territorial waters.,
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  11}## Limitations and Criticisms

Despite its clear definition, the concept of the territorial sea faces certain limitations and criticisms, particularly concerning its application and the ongoing tensions in some regions.

One primary limitation is the inherent right of innocent passage. While it serves to balance national sovereignty with global navigation, the interpretation of "innocent" can be a point of contention. What one state considers innocent passage, another might deem a threat to its security, particularly for warships or vessels conducting intelligence-gathering activities. This ambiguity can lead to diplomatic disputes and, in some cases, confrontations.

¹⁰Another significant challenge arises from overlapping maritime claims. When two or more states have coasts less than 24 nautical miles apart, their respective territorial seas would overlap. In such cases, international law requires them to reach an agreement on maritime boundaries, often using the median line principle. However, historical claims, strategic interests, and perceived rights to fishing rights and other marine resources can complicate these delimitations, leading to persistent territorial disputes.

⁹A prominent example is the ongoing dispute in the South China Sea, where multiple countries have overlapping claims to islands and maritime zones, including the territorial sea around various features. These disputes often involve contentions over historical rights and economic exploitation, and they can impact international trade and regional stability., ⁸S⁷uch situations highlight that while UNCLOS provides a legal framework, its implementation relies on the political will and cooperation of states.

Territorial Sea vs. Exclusive Economic Zone

The territorial sea and the exclusive economic zone (EEZ) are both maritime zones where a coastal state exercises certain rights, but they differ significantly in their legal status and the extent of those rights.

The key distinction lies in the degree of control. The territorial sea is essentially an extension of land, with near-absolute state authority (barring innocent passage). The EEZ, conversely, grants the coastal state specific economic rights over resources but maintains the international character of the waters and airspace for navigation and overflight.

FAQs

What is the primary purpose of a territorial sea?

The primary purpose of a territorial sea is to allow a coastal state to exercise its full sovereignty over a band of water adjacent to its coast, protecting its national security, enforcing its laws, and managing its natural resources.

Can foreign warships enter a nation's territorial sea?

Yes, foreign warships can enter a nation's territorial sea under the right of "innocent passage," meaning they must proceed continuously and expeditiously, without threatening the peace, good order, or security of the coastal state. Submarines, however, must navigate on the surface and show their flag.

¹### How is the breadth of the territorial sea measured?
The breadth of the territorial sea is measured from a designated baseline along the coast, which is typically the low-water line. From this baseline, the territorial sea extends up to 12 nautical miles seaward.

Is the territorial sea the same as international waters?

No, the territorial sea is distinct from international waters (also known as the high seas). The territorial sea is under the sovereignty of a specific coastal state, while international waters are beyond any national jurisdiction and are open for use by all nations.

What international agreement defines the territorial sea?

The United Nations Convention on the Law of the Sea (UNCLOS), adopted in 1982, defines the legal framework for the territorial sea and other maritime zones, providing a comprehensive set of rules for the use of the world's oceans.