The South China Sea: Flashpoints and Power Plays in 2026

As of April 2026, the South China Sea carries more strategic tension per square kilometer than any other body of water in the world. Roughly $3 trillion in annual trade passes through it. Multiple countries claim overlapping portions. China has built military bases on reefs that were underwater twenty years ago. The United States conducts freedom of navigation operations to dispute those claims. Incidents occur monthly. A single miscalculation could trigger a crisis.

What the South China Sea actually is

The South China Sea is the semi-enclosed body of water bounded by China to the north, the Philippines to the east, Malaysia and Brunei to the south, and Vietnam to the west. Taiwan sits at its northern edge. It contains the Spratly Islands, the Paracel Islands, the Scarborough Shoal, and hundreds of other small features — some are islands, some are reefs that disappear at high tide, some are underwater banks that barely exist at all.

The economic stakes are enormous. Roughly one-third of global maritime trade passes through the South China Sea. It is also believed to hold significant oil and natural gas reserves (exact amounts are disputed). The fisheries feed hundreds of millions of people. Every country in the region has legitimate economic interests in these waters.

The nine-dash line

China's claim to the South China Sea is visualized by the 'nine-dash line' — a series of dashes drawn on Chinese maps that enclose approximately 90% of the sea. The line first appeared on Chinese maps in 1947 and was inherited by the People's Republic of China in 1949. Beijing has never fully clarified what the line legally means — whether it is a sovereignty claim to all the waters inside, a claim to only the features (islands and reefs), or something in between.

The nine-dash line is inconsistent with the UN Convention on the Law of the Sea (UNCLOS), which China ratified. Under UNCLOS, maritime rights are generated from land features — islands, reefs, and coastlines — through Exclusive Economic Zones (EEZs) of up to 200 nautical miles. A line drawn to encompass an entire sea without grounding in specific features has no basis in modern international law. China argues that historical usage provides a separate basis for its claim. Most international lawyers reject this.

The 2016 PCA ruling

In 2013, the Philippines brought a case against China at the Permanent Court of Arbitration in The Hague under UNCLOS. The case challenged the legal basis of the nine-dash line and several specific Chinese actions. China refused to participate in the proceedings and declared in advance that it would not accept any ruling.

In July 2016, the tribunal ruled overwhelmingly in favor of the Philippines. It found that the nine-dash line had no legal basis. It found that many of the features China was occupying were rocks or low-tide elevations that could not generate EEZ rights. It found that China had violated Philippine rights in specific incidents. The ruling was legally binding under UNCLOS.

China rejected the ruling and continued its activities as if it had never been issued. The ruling is still cited by every country that disputes Chinese claims, and it remains a significant legal and diplomatic tool. But it did not change Chinese behavior on the water.

Island-building campaign

Between 2013 and 2016, China engaged in one of the largest island-building campaigns in modern history. Dredgers pumped sand from the seafloor onto reefs, transforming them into artificial islands with runways, harbors, and buildings. By the end of the campaign, China had created approximately 3,200 acres of new land on seven features in the Spratly Islands.

These artificial islands were then militarized. Runways capable of supporting military aircraft. Anti-ship and anti-aircraft missiles. Radar stations. Naval facilities. Barracks for permanent garrisons. China publicly committed to not militarizing the islands in 2015. It was clearly militarizing them at the time. Satellite imagery made the contradiction undeniable.

The strategic effect was transformative. Before the island-building campaign, China could patrol the South China Sea but could not sustain a permanent forward presence. After the campaign, it had hardened military bases at the heart of the sea, capable of projecting air and naval power across the entire region. The balance shifted decisively in China's favor.

The claimants

Vietnam

Vietnam has the most extensive claims after China and the longest history of confrontation. Vietnamese and Chinese forces have fought naval battles in these waters — most notably in 1974 (when China seized the Paracel Islands from South Vietnam) and 1988 (when China killed dozens of Vietnamese sailors at Johnson South Reef). Vietnam occupies more features in the Spratlys than any other country except China. It has been quietly modernizing its military with an eye toward Chinese capability.

Philippines

The Philippines has been the most vocal opponent of Chinese expansion in recent years. The 2016 arbitration case was a Philippine initiative. Under the current government, the Philippines has reopened military bases to US forces, conducted joint patrols with the US and Japan, and publicized Chinese coercion in real time with satellite imagery and video. The confrontation over the Second Thomas Shoal — where Philippine forces maintain a tiny garrison on a rusting beached ship — has become a near-constant flashpoint.

Malaysia

Malaysia has a quieter but real dispute with China over oil and gas exploration in waters Malaysia considers part of its EEZ. Chinese coast guard vessels have repeatedly interfered with Malaysian exploration activities. Malaysia has generally pursued quiet diplomacy rather than public confrontation, but its military has been expanding its maritime surveillance and response capabilities.

Indonesia

Indonesia is not a formal claimant to the Spratly or Paracel islands. But the nine-dash line clips into Indonesian-claimed waters around the Natuna Islands. Chinese fishing fleets, escorted by coast guard vessels, regularly encroach on the area. Indonesia has pushed back with increasing firmness, stationing forces on the Natuna Islands and conducting public exercises. Jakarta's position has hardened significantly since 2020.

Chinese tactics: the grey zone

China's operational approach in the South China Sea is distinctive. It rarely uses its regular navy for confrontations with other claimants. Instead, it uses the China Coast Guard (the largest coast guard in the world) and the 'maritime militia' — armed fishing vessels that operate as an unofficial paramilitary force.

This approach keeps confrontations below the threshold of military conflict while steadily expanding Chinese control. Water cannons. Ramming. Blocking. Physical harassment of other countries' vessels. These are serious and sometimes dangerous incidents, but they rarely result in fatalities or trigger a military response. Over years, they have changed facts on the water.

Critics call this 'cabbage strategy' (layers of vessels surrounding a disputed feature), 'salami slicing' (small steps that collectively change the status quo), or 'grey zone warfare.' The tactics are effective precisely because they are hard to respond to. How does the Philippines or Vietnam escalate against water cannons without looking like the aggressor? How does the US military intervene in what is technically a law enforcement matter?

US freedom of navigation operations

The United States conducts Freedom of Navigation Operations (FONOPs) in the South China Sea on a regular basis. US warships sail within 12 nautical miles of Chinese-claimed features, demonstrating that the US does not recognize the Chinese claims and that these are international waters. China always protests. Sometimes the protests are strident. Sometimes Chinese ships shadow US ships at close range.

FONOPs are important symbolically and legally but they do not reverse Chinese facts on the water. The US sails through. The Chinese facilities remain. The legal position of the US is preserved but the physical position of China is unchanged. Critics argue that FONOPs without backing them up with more concrete consequences may actually make things worse by demonstrating that the US is not willing to do more than sail past.

Japan, Taiwan, and the wider arc

Japan has its own maritime dispute with China over the Senkaku/Diaoyu Islands in the East China Sea. The pattern of Chinese coast guard incursions there parallels the South China Sea pattern. Japan has strengthened its southwestern island defenses significantly in recent years.

Taiwan is also a claimant in the South China Sea (it holds Itu Aba, the largest natural feature in the Spratlys). Taiwanese claims largely overlap with PRC claims, a remnant of the Chinese civil war era when both governments agreed on the basic territorial claim. The Taiwan issue sits at the intersection of the broader China-US strategic rivalry and is the single most dangerous component of it.

Together, these disputes form a connected arc of maritime tension from the Yellow Sea through the East China Sea through the Taiwan Strait and into the South China Sea. China's ambition to be the dominant power in each of these spaces is clear. The response of neighboring states and of the United States is the central story of Indo-Pacific security in this decade.

What could happen next

Scenario 1: Continued grey zone pressure

China continues to consolidate control through coast guard and militia tactics. Incidents occur but none escalate. Other claimants push back where they can but lack the capability to reverse Chinese gains. This is the baseline and has been the trajectory for a decade.

Scenario 2: A major incident

A Philippine sailor dies at Second Thomas Shoal. A Chinese and American ship collide during a close encounter. A Vietnamese patrol vessel is sunk. Any of these could trigger a crisis faster than political leaders can contain it. The probability grows with every year of continued pressure.

Scenario 3: A multilateral counter-coalition

ASEAN countries, together with Japan, Australia, and the US, build a more cohesive framework for pushing back against Chinese pressure. This has been discussed for years without much to show for it. ASEAN consensus requirements, economic dependence on China, and internal political divisions have prevented more forceful collective action.

Scenario 4: De-escalation through negotiation

China and ASEAN finalize a Code of Conduct for the South China Sea that provides real constraints on activity. This has been under negotiation since 2002 without significant progress. Periodic announcements of progress have not translated into substantive agreements. A genuine breakthrough remains possible but would require Chinese concessions that Beijing has not so far been willing to make.

The bottom line

The South China Sea is the clearest test case of whether the rules-based international order that developed after 1945 can survive a major power that rejects parts of it. China has shown that it can change facts on the water faster than the international community can respond. Other states have shown that they can push back through diplomacy, arbitration, and alliance-building but cannot reverse Chinese gains. The result is a new kind of maritime order — one where legal rules and physical reality are increasingly disconnected. How long that disconnection can persist without a crisis is the question this decade will answer.