The Rule on ‘Territorial Sea’ vs ‘Exclusive Economic Zone’ (EEZ)

I. Introduction

This memorandum provides an exhaustive analysis of the distinct legal regimes governing the territorial sea and the Exclusive Economic Zone (EEZ) under contemporary international law. The primary sources of law are the 1982 United Nations Convention on the Law of the Sea (UNCLOS) and customary international law. The central inquiry is to delineate the spatial extent, legal nature, and the bundle of sovereign rights and jurisdiction accorded to the coastal state within each maritime zone, while also clarifying the rights of other states. A clear understanding of this distinction is fundamental to resolving issues pertaining to navigation, resource exploitation, marine scientific research, environmental protection, and national security.

II. Statement of Issues

The principal issues are: (1) the legal definition and spatial scope of the territorial sea and the EEZ; (2) the nature of coastal state sovereignty and sovereign rights within each zone; (3) the specific rights and jurisdictions of the coastal state; (4) the corresponding rights and freedoms of other states; (5) the legal basis for claims and delimitation between adjacent or opposite states; and (6) the practical implications of these differing regimes for state practice and dispute resolution.

III. Applicable Laws and Sources

The primary legal instruments are: the 1982 United Nations Convention on the Law of the Sea (UNCLOS), widely accepted as reflecting customary international law on most provisions discussed herein; the 1958 Geneva Conventions on the Law of the Sea, where still applicable between certain states; relevant jus cogens norms; and the corpus of customary international law as evidenced by state practice and opinio juris. Judicial decisions from the International Court of Justice (ICJ) and the International Tribunal for the Law of the Sea (ITLOS), along with arbitral awards, provide authoritative interpretations.

IV. Definition and Spatial Scope

The territorial sea is a belt of sea adjacent to a coastal state’s baselines, over which the state exercises sovereignty, subject to the right of innocent passage. Its breadth extends up to a limit not exceeding 12 nautical miles from the baselines (UNCLOS Article 3). The Exclusive Economic Zone (EEZ) is an area beyond and adjacent to the territorial sea, extending up to 200 nautical miles from the baselines (UNCLOS Article 57). Within this zone, the coastal state is granted specific sovereign rights and jurisdiction, but it does not possess full sovereignty. The EEZ is therefore a sui generis zone, distinct from both the territorial sea and the high seas.

V. Nature of Coastal State Authority

In the territorial sea, the coastal state exercises sovereignty extending to the airspace above, the water column, the seabed, and subsoil. This sovereignty is inherent and plenary, albeit expressly limited by the right of innocent passage for foreign ships (UNCLOS Article 2). In contrast, in the EEZ, the coastal state does not have sovereignty but rather a functional set of “sovereign rights for the purpose of exploring and exploiting, conserving and managing the natural resources” of the waters, seabed, and subsoil, and jurisdiction over certain artificial islands, marine scientific research, and marine environmental protection (UNCLOS Article 56). These rights are not inherent; they must be claimed by the coastal state.

VI. Specific Rights and Jurisdictions

Within the territorial sea, the coastal state’s rights are comprehensive: legislative and enforcement jurisdiction over all matters (criminal, civil, administrative), subject to innocent passage; control over archipelagic sea lanes passage where applicable; the right to establish laws relating to innocent passage; and the exclusive right to exploit all resources. Within the EEZ, the coastal state’s rights are specifically enumerated: sovereign rights over all living and non-living resources; jurisdiction over the establishment and use of artificial islands, installations, and structures; marine scientific research; and the protection and preservation of the marine environment (UNCLOS Article 56). It has limited enforcement jurisdiction to secure these rights.

VII. Rights of Other States

The rights of other states differ fundamentally between the two zones. In the territorial sea, the primary right is that of innocent passage for all foreign ships (UNCLOS Articles 17-26). Warships are also entitled to innocent passage, though they may be subject to specific regulations. Overflight is not permitted without the coastal state’s consent. In the EEZ, all states enjoy the freedoms of navigation, overflight, and the laying of submarine cables and pipelines, and other internationally lawful uses of the sea related to these freedoms (UNCLOS Article 58(1)). These are high seas freedoms, exercised with due regard to the rights of the coastal state.

Comparative Table: Territorial Sea vs. EEZ

VIII. Delimitation Between States

The rules for delimiting overlapping maritime claims differ. For the territorial sea between states with opposite or adjacent coasts, UNCLOS Article 15 provides for an equidistance median line, unless historic title or other special circumstances require a different boundary. For the EEZ and continental shelf, UNCLOS Articles 74 and 83 mandate delimitation “by agreement on the basis of international law… to achieve an equitable solution.” This has been interpreted by the ICJ to involve a three-stage methodology: drawing a provisional equidistance line, considering relevant circumstances that may adjust it (e.g., coastal geography, proportionality), and testing for disproportionality.

IX. Legal and Practical Implications

The distinction carries significant implications. In the territorial sea, security interests are paramount; a coastal state may temporarily suspend innocent passage for security reasons (UNCLOS Article 25(3)). In the EEZ, military activities by foreign states are a contentious issue, often hinging on whether they constitute an exercise of navigation/overflight freedoms or are inconsistent with the coastal state’s resource-related rights. Marine scientific research in the EEZ requires the coastal state’s consent, which must not be withheld in normal circumstances for pure research (UNCLOS Article 246). Enforcement actions, such as boarding a foreign vessel, are strictly circumscribed in the EEZ compared to the territorial sea.

X. Conclusion

The territorial sea and the EEZ represent two fundamentally distinct legal constructs in the law of the sea. The territorial sea is an area of state sovereignty, subject to the specific limitation of innocent passage. The EEZ is a zone of functional sovereign rights and jurisdiction, wherein the coastal state manages resources while other states retain significant high seas freedoms. The 12-mile and 200-mile limits, respectively, create a layered maritime jurisdiction. Confusion or conflation of these regimes can lead to serious international disputes. All legal analysis concerning coastal state authority must therefore begin with a precise determination of the maritime zone in which the activities in question occur.