An Exclusive Economic Zone (EEZ) is a sea zone extending 200 nautical miles from a coastal nation’s baseline, within which that state holds sovereign rights over natural resources and certain economic activities. EEZs were formally codified under UNCLOS in 1982 and now govern roughly 40% of the world’s ocean surface.
The ocean has never been truly lawless. For centuries, nations have competed—sometimes violently—to assert control over maritime resources, trade routes, and strategic waterways. The concept of the Exclusive Economic Zone represents one of the most consequential developments in modern international law, transforming how the world understands oceanic sovereignty and the equitable distribution of marine wealth.
From the fisheries of the North Atlantic to the mineral-rich seabeds of the South China Sea, EEZs sit at the heart of some of the most pressing geopolitical disputes of the 21st century. Understanding what they are, how they function, and why they matter is essential for anyone seeking to make sense of international relations, maritime law, or global resource policy.
The Legal Foundation of Exclusive Economic Zones
The modern EEZ framework traces its origins to the United Nations Convention on the Law of the Sea (UNCLOS), which was opened for signature in 1982 and entered into force in 1994. UNCLOS—often described as the “constitution of the oceans”—established a comprehensive legal regime governing the rights and responsibilities of nations with respect to their use of the world’s seas.
Under Article 55 through Article 75 of UNCLOS, an Exclusive Economic Zone extends up to 200 nautical miles (approximately 370 kilometers) from a coastal state’s baseline, which is typically the low-water line along the coast. Within this zone, the coastal state exercises sovereign rights for the purpose of exploring, exploiting, conserving, and managing natural resources—both living (such as fish stocks) and non-living (such as oil, gas, and mineral deposits on or beneath the seabed).
Critically, EEZ rights are distinct from full territorial sovereignty. Foreign vessels retain the right of freedom of navigation and overflight within another state’s EEZ, provided they do not engage in resource exploitation activities without permission. This distinction between sovereign rights and full sovereignty is one of the more nuanced aspects of international maritime law.
The Historical Development of Maritime Jurisdiction
The concept underlying the EEZ did not emerge fully formed from the 1982 UNCLOS negotiations. Its roots stretch back several decades, shaped by a combination of postcolonial resource nationalism and the practical need to manage fish stocks that were being rapidly depleted by distant-water fishing fleets.
A pivotal early development came in 1945 with the Truman Proclamation, through which the United States unilaterally asserted jurisdiction over the natural resources of the continental shelf adjacent to its coastline. This declaration triggered a wave of similar proclamations from Latin American nations throughout the late 1940s and 1950s, most notably Chile, Ecuador, and Peru—states with rich fishing grounds off their Pacific coasts—which claimed 200-nautical-mile fishing zones as early as 1952 through the Declaration of Santiago.
By the time UNCLOS negotiations began in earnest during the Third United Nations Conference on the Law of the Sea (1973–1982), the principle of extended coastal state jurisdiction over adjacent marine resources had gained substantial international momentum. The formal codification of the EEZ within UNCLOS represented a compromise between the resource interests of coastal states and the navigational interests of maritime powers.
The Scope of Sovereign Rights Within an EEZ
The rights afforded to a coastal state within its EEZ are both broad and carefully delineated. On the resource side, the coastal state holds exclusive authority over fisheries management, offshore energy development (including oil, gas, and increasingly wind energy), and the exploitation of seabed minerals. States also possess jurisdiction over marine scientific research conducted within their EEZ and over the construction and regulation of artificial islands and structures.
However, these rights come paired with responsibilities. UNCLOS obligates coastal states to manage living resources to prevent overexploitation, to determine their own harvesting capacity, and to grant other states access to any surplus catch through negotiated agreements. This conservation mandate reflects a recognition that the EEZ regime serves not only the interests of individual states but also the long-term health of global marine ecosystems.
Economically, the stakes are enormous. According to estimates by the National Oceanic and Atmospheric Administration (NOAA), EEZs collectively encompass approximately 38–40% of the world’s total ocean surface. The resources contained within these zones—fisheries alone valued in the hundreds of billions of dollars annually—make EEZ governance a matter of critical national and international economic importance.
Overlapping Claims and Territorial Disputes
Where EEZ rights are unambiguous and undisputed, they function as an effective and largely self-executing legal framework. The more complicated reality, however, is that a significant proportion of the world’s EEZs overlap with those of neighboring states, particularly in semi-enclosed seas and regions of closely spaced island chains.
The South China Sea provides perhaps the most prominent contemporary example of EEZ-related conflict. China’s expansive maritime claims—formalized through the so-called “nine-dash line” that encompasses much of the South China Sea—directly contradict the EEZ entitlements of Vietnam, the Philippines, Malaysia, Brunei, and Indonesia under UNCLOS. In 2016, an Arbitral Tribunal convened under UNCLOS ruled in favor of the Philippines, finding that China’s historical claims had no legal basis under international law. China rejected the ruling entirely, and the underlying disputes remain unresolved.
Similar tensions exist in other regions. The Arctic Ocean is increasingly contested as melting sea ice opens new shipping routes and reveals previously inaccessible resource deposits, prompting competing EEZ claims from Russia, Canada, Denmark (via Greenland), Norway, and the United States. In the Eastern Mediterranean, overlapping EEZ claims between Greece, Turkey, Cyprus, and Libya have generated repeated diplomatic and, at times, military confrontations.
The Role of Islands and Rocks in EEZ Delimitation
One of the more technically complex aspects of EEZ law concerns the maritime entitlements of islands, rocks, and low-tide elevations. Under Article 121 of UNCLOS, islands—defined as naturally formed land areas above water at high tide—generate their own full suite of maritime zones, including a 200-nautical-mile EEZ. This provision has made small, remote islands strategically significant far beyond their physical size or population.
Rocks that cannot sustain human habitation or independent economic life, however, generate only a territorial sea of 12 nautical miles and no EEZ. The distinction between an “island” and a “rock” has therefore become a matter of considerable legal contention, as states seek to maximize their oceanic jurisdiction through the classification of remote land features.
The Okinotorishima dispute between Japan and China illustrates this tension clearly. Japan considers Okinotorishima—a coral reef that barely emerges above the high-tide mark—to be an island capable of sustaining an EEZ, a position China contests. The outcome directly affects the jurisdictional boundaries of both nations across a vast stretch of the Pacific Ocean.
The Economic and Strategic Significance of EEZs
Quantifying the economic value embedded within the world’s EEZs requires accounting for a diverse portfolio of resources. Marine fisheries within EEZs support the livelihoods of hundreds of millions of people globally and contribute directly to national food security. Offshore hydrocarbon extraction—oil and natural gas—occurs almost entirely within EEZ boundaries, making these zones central to both domestic energy production and export revenue.
Emerging sectors add further dimensions to EEZ value. Offshore wind energy development is expanding rapidly in European EEZs, with the North Sea emerging as a major hub. Deep-sea mining for polymetallic nodules, cobalt-rich crusts, and seafloor massive sulfides represents a frontier industry that could, if developed responsibly, provide critical minerals essential to battery technology and the global energy transition.
Strategic and military dimensions also attach to EEZ control. While UNCLOS guarantees freedom of navigation through EEZs, disputes over the permissibility of military surveillance activities within foreign EEZs—a persistent source of tension between the United States and China—demonstrate that the legal text does not resolve all interpretive ambiguities.
EEZs and the Future of Ocean Governance
The EEZ framework, now four decades old in its UNCLOS form, faces mounting challenges from forces that were barely imaginable when the convention was drafted. Climate change is altering the distribution of fish stocks, pushing species into new jurisdictional waters and disrupting established fisheries management arrangements. Sea level rise threatens the basepoints from which EEZ measurements are calculated, raising the unsettling prospect that low-lying states could lose their maritime zones entirely as their coastlines erode or submerge.
The international community is also grappling with how to govern the “high seas”—the approximately 64% of the ocean that lies beyond national EEZ jurisdiction. In 2023, United Nations member states adopted the Agreement on Biodiversity Beyond National Jurisdiction (BBNJ Agreement), a landmark treaty designed to establish marine protected areas and regulate resource extraction in international waters. The BBNJ Agreement reflects a growing recognition that the EEZ regime, for all its achievements, addresses only part of the ocean governance challenge.
The Enduring Relevance of Maritime Law
Exclusive Economic Zones represent a foundational achievement of modern international law—a framework that transformed chaotic maritime competition into a structured, rules-based system governing nearly half the world’s ocean surface. The framework is imperfect, contested in many of its applications, and increasingly strained by geopolitical rivalry and environmental change. Yet its core logic—that coastal states bear both rights over and responsibilities for the marine resources adjacent to their shores—remains as valid and necessary today as when UNCLOS was first conceived.
As resource scarcity intensifies, as emerging technologies unlock new forms of oceanic exploitation, and as the physical character of coastlines changes beneath the pressure of a warming climate, the principles embedded in EEZ law will continue to shape how nations negotiate their relationships with the sea. Studying the EEZ framework, its foundations, its disputes, and its future is, in this sense, an exercise in understanding the structures that govern not just the ocean, but the global order itself.