Understanding the Context

What is the Territorial Sea?

The territorial sea refers to the strip of coastal waters extending up to 12 nautical miles (approximately 22.2 kilometers) from a country’s baseline—typically the low-water line along the coast. Within this maritime zone, the coastal state exercises full sovereignty, similar to its land territory, allowing control over shipping, resource use, environmental regulation, and security enforcement.

Legal Foundations: UNCLOS and International Law

Key Insights

The legal framework governing territorial seas is most comprehensively established by the United Nations Convention on the Law of the Sea (UNCLOS), adopted in 1982 and in force since 1994. Under Article 3 of UNCLOS, every coastal state has sovereign rights within its territorial sea, including:

• Sovereign jurisdiction over the air space, seabed, and waters.
  
• Authority to enforce laws related to immigration, customs, pollution, and resource exploitation.
  
• The right to innocent passage for foreign vessels—meaning non-military ships and aircraft may traverse these waters provided they do not threaten the peace, good order, or security of the coastal state.

While UNCLOS sets the 12-nautical-mile limit as the standard, coastal states may claim up to 24 nautical miles for special geographic conditions under certain conditions, though military navigation rights generally apply continuously.

Key Characteristics of Territorial Sea Sovereignty

Final Thoughts

1. Full Sovereignty Within Limits
   Coastal states govern every aspect—economic, environmental, and security-related—within their territorial sea. This includes managing fisheries, seabed mining, and coastal ecosystems.

2. Innocent Passage
   Foreign ships, regardless of flag state, are allowed innocent passage, defined as continuous and expeditious transit that does not engage in activities such as weapons drills, pollution, or surveillance. Coastal states may validate passage requests and suspend it if justified.

3. Suspension of Rights
   Sovereignty can be temporarily suspended in specific zones for security or environmental protection, such as establishing an Exclusive Economic Zone (EEZ) overlay, though encroachment risks diplomatic disputes.

4. Maritime Boundaries
   Baselines, from which territorial sea extent is measured, must follow low-water lines consistently; artificial islands or moderne constructions do not expand territorial limits.

Importance of Territorial Seas in Global Affairs