Islands have long been more than just landmasses surrounded by water. In the theater of global geopolitics, they function as strategic outposts, economic prizes, and flashpoints for international rivalry. Their location often commands critical sea lanes, provides forward basing for military forces, and grants control over vast maritime resources. The significance of islands is amplified by the United Nations Convention on the Law of the Sea (UNCLOS), which grants coastal states exclusive economic zones (EEZs) extending up to 200 nautical miles from their shores. This legal framework transforms even a tiny atoll into a claim over hundreds of thousands of square kilometers of ocean, making islands indispensable assets in the modern competition for power and resources.

The Role of Islands in Military Strategy

From ancient naval empires to modern superpowers, islands have been coveted for their military advantages. Their natural isolation offers inherent defensibility, while their position along strategic waterways allows for power projection and deterrence.

Forward Operating Bases and Power Projection

Islands provide unsinkable aircraft carriers, enabling nations to station air and naval assets far from their home shores. The United States maintains major bases on Guam, Okinawa, and Diego Garcia, allowing rapid response across the Pacific and Indian Oceans. Similarly, China has transformed artificial islands in the South China Sea into militarized outposts equipped with airstrips, radar, and missile systems. These bases significantly reduce response times and extend a nation's strategic reach.

Control of Chokepoints

Many islands lie adjacent to vital maritime chokepoints—narrow straits through which a large percentage of global trade must transit. The Strait of Malacca, for example, is flanked by Indonesian islands such as Sumatra and the Riau Archipelago. Control over these islands can influence the flow of oil, goods, and naval traffic. Other critical chokepoints influenced by islands include the Bab el-Mandeb (near Socotra), the Strait of Hormuz (near Qeshm and Hormuz islands), and the Taiwan Strait.

Surveillance and Intelligence

Islands offer ideal locations for signals intelligence (SIGINT) and radar stations. The U.S. maintains a major intelligence facility on Diego Garcia, and Australia operates Joint Facility Pine Gap near Alice Springs (though not an island). In the Arctic, Norway's Svalbard archipelago hosts research stations that also gather intelligence on Russian naval movements.

Strategic Denial

Nations also use islands to deny access to rivals. China's island-building campaign aims to create a "Great Wall of Sand" that restricts U.S. naval freedom of navigation. Similarly, Russia's militarization of the Kuril Islands (disputed with Japan) serves to block Japanese and U.S. access to key Pacific routes.

Economic Significance of Islands

Beyond military utility, islands are economic engines. Their resources and geographical positioning generate immense value, but also create disputes.

Exclusive Economic Zones (EEZs)

Under UNCLOS, an island—inhabited or not—can generate an EEZ of up to 200 nautical miles. For a small island, this can mean jurisdiction over a resource-rich area comparable to the landmass of a continent. For example, the French territory of Clipperton Island, with a land area of just 1.7 square kilometers, controls an EEZ of nearly 435,000 square kilometers. This incentivizes nations to claim even the most desolate rocks.

Fisheries and Aquaculture

Islands often sit atop productive fishing grounds due to nutrient-rich currents. The Pacific Island nations of Kiribati, Tuvalu, and the Solomon Islands rely heavily on tuna fisheries, which contribute a major share of their GDP. Control over surrounding waters is essential for food security and economic income.

Energy and Mineral Resources

Offshore oil and gas deposits frequently lie within island EEZs. The South China Sea is estimated to hold 11 billion barrels of oil and 190 trillion cubic feet of natural gas, driving much of the territorial disputes. Additionally, seabed nodules rich in cobalt, nickel, and rare earth elements are found near islands in the Pacific, such as around the Cook Islands and the Clarion-Clipperton Zone.

Tourism and Strategic Services

Tourism is the lifeblood of many island economies—the Maldives, Bahamas, and Seychelles derive over 30% of their GDP from it. Islands also host offshore financial centers (e.g., Cayman Islands, Bermuda) and provide tax advantages for global corporations, adding to their economic heft.

Geopolitical Tensions Surrounding Islands

Islands are among the most frequent flashpoints in international relations. Their legal status, historical ownership, and resource potential ignite conflicts that can escalate to military confrontation.

The South China Sea Disputes

The centerpiece of modern island geopolitics is the South China Sea, where China, Vietnam, the Philippines, Malaysia, Brunei, and Taiwan claim overlapping sovereignty over the Spratly and Paracel Islands. China has built artificial islands on submerged reefs, constructing runways, ports, and missile defenses. The 2016 Permanent Court of Arbitration ruling against China's claims (the "Philippines v. China" case) was largely ignored by Beijing. The U.S. continues freedom of navigation operations to challenge China's assertions.

The Senkaku/Diaoyu Islands

These uninhabited islets in the East China Sea are administered by Japan but claimed by China and Taiwan. The dispute has led to naval standoffs and a surge in nationalist sentiment. The islands sit near rich fishing grounds and potential oil reserves. China's deployment of maritime militia vessels near the islands is a constant source of tension.

The Falkland Islands

The Falklands remain a deeply contested territory between the United Kingdom and Argentina, 40 years after the 1982 war. The residents voted overwhelmingly to remain British, but Argentina maintains a constitutional claim. The islands' surrounding waters contain valuable fisheries and suspected oil reserves. The dispute periodically reignites diplomatic and economic pressure.

The Kuril Islands

Russia occupies the four southern Kuril Islands (which Japan calls the Northern Territories), seized at the end of World War II. The dispute has prevented a formal peace treaty between the two nations. Japan seeks their return, while Russia has militarized the islands, stationing advanced anti-ship and anti-aircraft systems. The strategic location of the Kurils controls the entrance to the Sea of Okhotsk, a crucial bastion for Russia's ballistic missile submarines.

Other Notable Disputes

Additional conflicts include the Dokdo/Takeshima islands (South Korea vs. Japan), the Liancourt Rocks, the Diaoyu/Senkaku islets, the Paracel Islands (China vs. Vietnam), and the islands in the Aegean Sea (Greece vs. Turkey). Each dispute carries the potential for escalation, often fueled by domestic politics and resource competition.

Environmental and Climate Challenges

Islands, particularly low-lying atoll nations, are on the front lines of climate change. Rising sea levels threaten their physical existence, while extreme weather events devastate infrastructure and ecosystems.

Sea Level Rise and Sovereignty

If an island becomes uninhabitable or submerges, what happens to its EEZ and sovereignty? International law is ambiguous. Nations like Kiribati, Tuvalu, and the Maldives have purchased land abroad and explored the concept of "climate refugees" or "continued statehood." The potential loss of habitable land could trigger mass displacement and legal battles over maritime boundaries.

Biodiversity at Risk

Islands harbor unique ecosystems, often with high endemism. The Galápagos Islands, Madagascar, and Sri Lanka are biodiversity hotspots. Climate change, invasive species, and habitat destruction threaten these fragile environments. Protecting island biodiversity is not only an ecological concern but also a geopolitical one, as environmental degradation can undermine economic stability.

Natural Disasters and Resilience

Islands in the Pacific, Caribbean, and Indian Ocean are frequently hit by hurricanes, typhoons, and tsunamis. For example, the 2004 Indian Ocean tsunami devastated island communities, and Hurricane Maria in 2017 destroyed much of Dominica. Building resilient infrastructure requires significant investment, often from international aid. This dependence can create leverage for donor nations.

International law provides the rules of the game for island disputes, but interpretation remains contested.

UNCLOS and Article 121

Article 121 of UNCLOS distinguishes between "rocks which cannot sustain human habitation or economic life of their own" and "islands." Rocks generate no EEZ or continental shelf, while islands do. But the definition is vague. The 2016 South China Sea ruling determined that features like Spratly Island and Itu Aba are rocks, not islands. China has not accepted this interpretation. The ambiguity encourages nations to build artificial structures to support habitation and economic activity.

Historic Claims and Dispute Resolution

Some nations base claims on historical discovery or "historic waters." China's nine-dash line is an example of such a claim, which was rejected by the international tribunal. Other nations, like Japan and South Korea, rely on effective control and international recognition. The International Court of Justice and the Permanent Court of Arbitration have arbitrated several island disputes, but compliance is voluntary and often ignored by powerful states.

Artificial Islands

The status of artificial islands is also contested. Under UNCLOS, they do not generate their own EEZ or continental shelf. However, China's construction of military facilities on artificial features challenges this principle. The militarization of artificial islands has escalated tensions and raised questions about the future of the law of the sea.

Case Studies of Strategic Islands

Guam

Guam, a U.S. territory in the Western Pacific, hosts Andersen Air Force Base and Naval Base Guam. It is a critical hub for bomber rotations, submarine operations, and missile defense. The island is within range of Chinese and North Korean missiles, making it both a forward base and a potential target. The U.S. has invested heavily in Guam's defenses, including Terminal High Altitude Area Defense (THAAD) systems and the construction of a new Marine Corps base.

Hainan Island

China's southernmost province, Hainan, has transformed into a military and economic powerhouse. It hosts the Yulin Naval Base, a major submarine base with underground facilities. Hainan is also the site of China's newest aircraft carrier base and a key space launch center. Additionally, China has designated Hainan as a free-trade port, aiming to create a regional economic hub. The island's position overlooking the South China Sea makes it central to China's maritime strategy.

Diego Garcia

Located in the central Indian Ocean, Diego Garcia is a joint U.S.-UK military base. It hosts B-2 and B-52 bombers, naval support facilities, and a large fuel storage depot. The base played a crucial role in operations in Afghanistan and Iraq. Its isolated location provides strategic depth, but the base has also been controversial due to the forced removal of the Chagossian people. The base's lease runs until 2036, and its importance is growing as India-China competition intensifies.

Okinawa

Okinawa Prefecture, Japan, hosts approximately 70% of U.S. military facilities in Japan. Marine Corps Air Station Futenma and Kadena Air Base are key assets for power projection in East Asia. However, the heavy presence has caused local opposition due to noise, accidents, and crimes. The ongoing debate over the relocation of Futenma base to Henoko Bay reflects the tension between strategic necessity and local sovereignty.

Several emerging trends will shape the role of islands in coming decades.

Arctic Islands and New Sea Routes

As Arctic ice melts, islands like Svalbard, Greenland, and Canada's Arctic archipelago gain new strategic importance. These islands sit along the Northern Sea Route, which could become a major shipping lane. Nations are expanding their military presence: Russia has reopened Soviet-era bases on islands like Alexandra Land and Kotelny Island. Denmark and Canada have increased patrols around their Arctic territories. Resource extraction (oil, gas, minerals) will also accelerate disputes.

Artificial Islands and Hybrid Warfare

China's island-building campaign is likely to be replicated by other nations. India, Vietnam, and the Philippines are all investing in land reclamation on reefs and shoals. Artificial islands can serve as bases for navy, coast guard, and fisheries enforcement, blurring the line between civilian and military activities. They also enable "gray zone" tactics—actions just short of armed conflict—which challenge traditional deterrence.

Climate-Driven Migration and Geopolitics

As some island nations become uninhabitable, their populations may move to larger countries. This migration can alter demographics and create new diplomatic leverage. For example, Tuvalu has sought agreements with Australia and New Zealand to accept its citizens in exchange for maintaining its maritime zones. Climate change could also reshape maritime boundaries if baselines shift due to sea-level rise, forcing renegotiation of EEZs.

Conclusion

Islands are far more than picturesque resorts or remote dots on the map. They are linchpins of military strategy, contested prizes in resource wars, and vulnerable frontlines of climate change. Understanding their strategic importance requires a grasp of law, economics, history, and environmental science. As global competition intensifies—in the South China Sea, the Arctic, and beyond—islands will continue to shape the balance of power. Policymakers must navigate these dynamics carefully, balancing national interests with international stability. For anyone studying geopolitics, islands remain an essential, and often overlooked, piece of the puzzle.

External resources: For further reading, see the Council on Foreign Relations' backgrounder on South China Sea disputes, the Encyclopedia Britannica entry on UNCLOS, and the BBC's analysis of the Falkland Islands. Additional insights on island military bases can be found in RAND Corporation reports on posture in the Indo-Pacific.