Military Exercises in Another State’s EEZ: A Restrictive Interpretation

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Created: 12 May 2025

The growing frequency of naval drills in strategic waters has revived a critical legal question: May a state lawfully conduct military exercises inside another state’s Exclusive Economic Zone (EEZ) without consent? This issue sits at the intersection of international law, maritime security, and geopolitics, and remains one of UNCLOS’s most contested ambiguities.1

Although the United Nations Convention on the Law of the Sea (UNCLOS) carefully balances coastal state rights with the freedoms of other states, it is silent on whether foreign naval forces may perform combat simulations, live-fire drills, Anti-Submarine Warfare SONAR operations, missile tests, or electronic warfare inside another state’s EEZ. This silence has produced two opposing interpretations.2

Major naval powers assert a permissive view, claiming that such activities fall under “freedoms of navigation.” While many coastal and archipelagic states advance a restrictive view, arguing that intrusive military operations jeopardize sovereign rights, security, and marine resources.3

A closer examination of UNCLOS, and the principles underpinning it, reveals that the restrictive view is more consistent with the treaty’s text, object, and purpose.4

I.        What UNCLOS Actually Provides in the EEZ

The EEZ extends up to 200 nautical miles from a coastal state’s baselines. Beyond the 12‑nautical‑mile territorial sea, the area already forms part of the EEZ. Between 12 and 24 nautical miles, a coastal state may also claim a contiguous zone for enforcement purposes, but those waters are simultaneously part of the EEZ. Unlike the territorial sea, the EEZ does not confer full sovereignty. Instead, it grants the coastal state sovereign rights to explore, exploit, conserve, and manage natural resources, as well as jurisdiction over artificial islands, marine scientific research, and environmental protection.5

This arrangement, often described as functional sovereignty, gives the coastal state exclusive control over specific activities without treating the EEZ as sovereign territory. The purpose is clear: to protect the coastal state’s economic and environmental interests while permitting international navigation.6

Other states retain the freedoms of navigation and overflight, and “other internationally lawful uses of the sea” related to these freedoms. But these rights come with a crucial restriction: they must be exercised with due regard for the rights and duties of the coastal state.7

UNCLOS, therefore, envisions the EEZ as a balanced zone, not an unrestricted maritime arena.8

II.       The Divergent Interpretations

1.       The Permissive View

States with strong blue-water navies argue that UNCLOS’s reference to “other lawful uses of the sea” includes military operations, even inside foreign EEZs. They emphasize that:

  • UNCLOS does not explicitly prohibit military activities in the EEZ.
  • Navigational freedoms inherently cover warships.
  • Naval operations support global maritime security.

Under this view, foreign warships may freely conduct sonar sweeps, missile tests, surveillance, and hydrographic surveys without coastal state consent.9

2.       The Restrictive View

Many coastal states reject this interpretation, maintaining that foreign military operations in the EEZ require consent, especially those involving:

  • Active sonar and ASW drills
  • Torpedo or live-fire exercises
  • Electronic warfare and spectrum interference
  • Intelligence collection and hydrographic surveys

These activities are not mere navigation. They are military, security-related, and intrusive. They directly affect the coastal state’s ability to safeguard its resources, environment, and territorial defense.10

This restrictive position is firmly rooted in UNCLOS’s due regard obligation, the peaceful purposes principle, and the UN Charter’s prohibition on the threat or use of force.11

III.       Military Exercises Are Not “Ordinary Uses” of the EEZ

UNCLOS was designed as a negotiated balance: coastal states gained expanded resource jurisdiction, while maritime powers preserved navigation rights. Yet this balance was never intended to authorize unrestrained foreign military operations in sensitive maritime areas.12

Allowing foreign naval forces to conduct combat simulations, surveillance drills, or reconnaissance exercises near another state’s coast would expose the coastal state to:

  • Environmental threats (e.g., sonar-induced harm to marine mammals, seabed disturbance, and explosive damage)
  • Interference with energy exploration and offshore operations
  • Compromised maritime domain awareness
  • Strategic vulnerabilities, especially where foreign vessels shadow or map underwater terrain

These activities go far beyond navigational freedom. They are fundamentally security operations, incompatible with the resource-management focus of the EEZ regime.13

IV.      Due Regard and Peaceful Purposes: The Legal Foundation of the Restrictive View

1.       The Due Regard Obligation

UNCLOS requires all states exercising freedoms in the EEZ to have due regard for the coastal state’s rights. This is not a vague courtesy—it is a substantive obligation UNCLOS prohibits foreign states from undertaking activities that impair the coastal state’s rights to resource management, environmental supervision, or maritime safety. 14

Foreign military drills involving sensors, weapons, or reconnaissance exercises are inherently incompatible with due regard. They disrupt lawful EEZ uses and undermine the coastal state’s ability to manage its maritime space.15

2.       The Peaceful Purposes Principle

UNCLOS, echoing the UN Charter, requires all ocean uses to conform to peaceful purposes. While this does not forbid military vessels from transiting, it prohibits activities that:

  • threaten or intimidate coastal states,
  • undermine regional stability, or
  • constitute implied demonstrations of force.

Live-fire exercises, missile tests, electronic warfare, and reconnaissance or surveillance drills inside a foreign EEZ carry an unmistakable coercive character. Even without actual conflict, such actions blur the line between lawful presence and power projection.16

Together, due regard and peaceful purposes impose a binding standard of maritime conduct that foreign states must respect when operating in another state’s EEZ.17

See Also: The EEZ Due Regard and Peaceful Purposes Explained.

V. Impact on Security and Policy

In regions such as the Indo‑Pacific, where strategic competition and overlapping maritime claims intensify, foreign military activities inside another state’s EEZ heighten risks of escalation, miscalculation, and environmental harm. In areas like the West Philippine Sea, these operations complicate resource development, ecological preservation, and national defense planning. 18

Requiring prior notification and consent represents a reasonable and stability‑oriented application of UNCLOS, one that respects navigational freedoms while safeguarding coastal state interests.19

This approach does not obstruct legitimate cooperation, joint or multi-lateral exercises; rather, it ensures transparency, mutual respect, and predictability in maritime operations.20

Conclusion

UNCLOS was crafted to promote stability, equity, and the peaceful use of the oceans—not naval dominance. Reading its silence as permission for intrusive military exercises inside another state’s EEZ would erode this foundation. 21

The restrictive interpretation, grounded in sovereign rights, the due regard obligation, and the peaceful purposes principle, remains the most coherent and responsible reading of UNCLOS. In an era of growing maritime tension, it provides a path that protects coastal state security while strengthening a rules‑based maritime order.22

  1. United Nations Convention on the Law of the Sea pmbl., Dec. 10, 1982, 1833 U.N.T.S. 3 [hereinafter UNCLOS]. ↩︎
  2. Id. arts. 56, 58. ↩︎
  3. Id. art. 58(3). ↩︎
  4. Id. pmbl. ↩︎
  5. Id. arts. 33, 56, 60, 192–194. ↩︎
  6. Id. art. 56. ↩︎
  7. Id. art. 58(3). ↩︎
  8. Id. pmbl. ↩︎
  9. Id. art. 58. ↩︎
  10. Id. arts. 56, 192–194. ↩︎
  11. U.N. Charter art. 2(4), June 26, 1945, 1 U.N.T.S. XVI [hereinafter UN Charter]; UNCLOS art. 301. ↩︎
  12. UNCLOS pmbl. ↩︎
  13. Id. arts. 192–194, 206. ↩︎
  14. Id. art. 58(3). ↩︎
  15. Id. art. 56. ↩︎
  16. UNCLOS art. 301; U.N. Charter art. 2(4). ↩︎
  17. Id. ↩︎
  18. Philippines v. China, PCA Case No. 2013‑19, Award ¶¶ 119–123 (Perm. Ct. Arb. July 12, 2016). ↩︎
  19. UNCLOS arts. 56, 58. ↩︎
  20. Id. pt XV. ↩︎
  21. Id. pmbl. ↩︎
  22. Id. arts. 56, 301. ↩︎

 

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