South China Sea Dispute


The South China Sea is a resource rich and geopolitically strategic area that has precipitated a series of conflicts and diplomatic spats in the region. China, Vietnam, the Philippines, Taiwan, Indonesia, Malaysia, and Brunei have all made claims in the region throughout the past half-century, leading to skirmishes and legal issues. The South China Sea boasts rich and bountiful oil reserves and hosts a third of global maritime trade, and an estimated US$3.37 trillion worth of trade passes through the region each year. Thus, there are powerful economic, political, and strategic imperatives for asserting and maintaining power over this region. 

Tensions have worsened throughout the years as China continues to build artificial islands and actively militarizes the region. The US-China battle for supremacy in the international order has also raised the stakes in the region. The US has long criticized China’s construction of islands and building of military facilities in the region, and is concerned they could be used to restrict free nautical movement. This can be largely attributed to the US$1.2 trillion worth of US-traded goods passing through the South China Sea each year. 

Agreements such as the United Nations Convention on the Law of the Sea (UNCLOS) exist to regulate maritime disputes and encourage free and open navigation, although vague wording has made it difficult to address South China Sea territorial disputes. National pride, trade and military ambitions, and historic and symbolic attachments have added fuel to the fire. Confrontations between aircraft carriers, fishing boats, bombers, and seaplanes manned by the various claimants in the region have resulted in fatal standoffs, protests, and bitter diplomatic relations.


Where: A marginal sea in the pacific. South of China, East of Vietnam, West of the Philippines, east of the Malay Peninsula and north of Borneo.

Deaths: Approx. 150

Number of Islands: 250

Trade worth of the South China Sea:  5.3 trillion worth of goods transit the region annually

Oil resources in the region: Approximately 11 billion barrels of untapped oil and 190 trillion cubic feet of natural gas

Value of  U.S. Trade: Approximately 1.2 trillion

Artificial Islands: 7 reclamation projects across 7 locations (Chinese projects)

Beijing: Reclaimed more than 3,200 acres since late 2015, more land than all other claimants 

The Philippines: Along with China, they both lay claim to the Scarborough Shoal (Huangyan Island in China) which is 160km from the Philippines and 500 miles from China.

Key actors

China has backed its territorial claims over all South China Sea islands with island-building and naval patrols. It claims that the islands in question have belonged to China since ancient times. China doesn’t believe that external military forces should have access to the South China Sea as they believe it lies within their Economic Exclusion Zone (EEZ). China’s sovereignty over the region has caused significant backlash as it denies the freedom of navigation to other states or access to resources.

The Philippines claims sovereignty over Spratly Islands and Scarborough Shoal. It invokes its’ geographical proximity to the latter—located 100 miles off its shores—as the basis for its claim. President Duterte continues to fight for the Philippines “right” to extract resources from the sea whilst attempting to settle differences with China.

Taiwan claims sovereignty over all the island groups in the region and jurisdiction over adjacent waters such Spratlys, Paracel, Pratas, Macclesfield Bank, and Taiping Island. Taiwan has faced extreme backlash from China, who continues to try to diminish Taiwan’s presence in the region.

Malaysia claims a portion of an area north of Borneo, which encompasses at least 12 features in the Spratlys. This area is within Malaysia’s maritime jurisdiction, but they remain relatively quiet about the issue.

Brunei holds claim (since 1984) to 200 square nautical miles of the South China Sea.Its claim includes Bombay Castle, Louisa Reef (claimed by Vietnam and China), Owen Shoal and Rifleman Bank of the Spratly Island chain.

Vietnam claims parts of the Spratly Islands (25 features) and the Paracel Islands based on historical evidence, economic development and international recognition. Vietnam has continuously come up against China’s extensive naval power and has been vocal against the Chinese offensive. 

The USA has long criticized China’s construction of islands and build-up of military facilities in the South China Sea, and is concerned they could be used to restrict free nautical movement—of considerable significance since an estimate $1.2 trillion of US-traded goods pass through this sea every year. Recently, the US has been pushing allies to carry out freedom of navigation operations as well. The U.S. believe that under the UN Convention of the Law of the Sea (UNCLOS), different claimants of the region should have access freely navigate the sea and conduct military operations within it.

Indonesia claims the center on the Natuna Sea, a resource-rich waterway north of Indonesia that also lies close to Vietnam exclusive economic zone. They have begun increasing their military presence in the disputed territory.

The Court arbitrated and ruled in favour of the Philippines in the case brought against China’s reclamation activities in the South China Sea. Unfortunately, lacks an enforcement mechanism

ASEAN is a ten-member regional body that includes Indonesia, Malaysia, the Philippines, Thailand, Brunei, Myanmar, Cambodia, Laos, and Vietnam. Holds regular consultations with China aimed at developing a multilateral framework toward greater cooperation and conflict resolution.

Russia’s presence is the South China Sea is rather new and although Russia has not put forward any claims towards the South China Sea, its involvement remains complex. This is due to Russia’s growing interest in the region, its strong relationship with Vietnam and its growing relationship with China as well the Philippines.

Japan gained exclusive rights over several South China Sea archipelagos and took control of the Pratas Islands from September 3, 1937. Japan relies upon the South China Sea for resources, oil and as an export route. Tensions between Japan and China continue over the East China Sea, specifically because Japan claimed the Diaoyu islands in 1895.

Timeline of the crisis

After Japan gained exclusive rights over several archipelagos in the South China Sea, Japan took control of the Pratas Islands.

The Japanese Imperial Navy invaded Hainan the following February. Japan’s invasion followed the Marco Polo Bridge Incident of July 1937, which was a battle between the Chinese National Revolutionary Army and the Japanese Imperial Army. This marked the beginning of the Japanese invasion of China.

After the Japanese surrender at the end of WWII, the U.S. took control of Japan. This involved the Ryukyu Islands, which held strategic significance in terms of the American imperative to thwart the spread of communism.

Under the Chiang Kai-shek government, China demarcated its territorial claims in South China Sea with an eleven-dash line, which claimed the waters adjacent to Malaysia, the Philippines and Vietnam.

Mao Zedong announced the formation of the People’s Republic of China (PRC), ending the civil war that broke out shortly after World War II. Defeated Nationalist leader Chiang Kai-shek escaped to Taiwan, where he created the ROC. 

The U.S. and forty-seven other nations signed the Treaty of Peace (PDF) with Japan in San Francisco, officially ending World War II. Japan renounced all claims to Korea, Taiwan, the Pescadores, and the Spratly Islands in the South China Sea.

China removed the Gulf of Tonkin portion, erasing two dashes from its original territorial claims, in effect reducing it to a nine-dash line.

After thorough geological surveys that took place between 1968 and 1969, a report published by the UN found significant energy deposits in the waters off the Diaoyu/Senkaku Islands between Taiwan and Japan.

The Philippines occupied five of the Spratly Islands and claimed the entire Western part of the archipelago.

The United States and Japan signed the Okinawa Reversion Treaty, in which Washington effectively returned full control of the Ryukyu Islands to Japan. The move was seen as reinforcing the U.S.-Japan security alliance. In response to the reversion treaty, the ROC and PRC began issuing claims to the islands, saying they had belonged to the Chinese since ancient times and have been administered by the province of Taiwan. Meanwhile, Japan viewed the reversion agreement with the United States as further validation of its sovereignty over the disputed islands.

China captured the Paracel Islands, which had previously been occupied by South Vietnam.

China and Japan formally re-established diplomatic relations after gradually rebuilding economic ties. In China, the failure of Mao’s Great Leap Forward (1958–1962) preceding the Cultural Revolution resulted in mass starvation that forced Beijing to reevaluate its domestic policies and look to Japan for aid. The Sino-Japanese reconciliation dovetailed the rapprochement between the United States and China—a change in official political allegiance from Taipei to Beijing that was a crucial factor in the establishment of diplomatic ties between Japan and China. Trade between Japan and China surged in the period after normalization, deescalating the first round of the Diaoyu/Senkaku Islands disputes.

South Vietnam occupied much of the Spratly Islands. A year after the Paris Peace Accords, which ended the U.S. involvement in the Vietnam War, Chinese forces occupied the western portion of the Paracel Islands, planting flags on several islands and seizing a South Vietnamese garrison. Vietnamese troops fled south and established the first permanent Vietnamese occupation of the Spratly Islands. Meanwhile, Beijing built a military installation, including an airfield and artificial harbor, on Woody Island, the largest of the Paracels. After the fall of Saigon and the reunification of Vietnam, the newly formed Socialist Republic of Vietnam upheld the South’s former claims to the Spratlys and Paracels. To this day, China maintains around one thousand troops in the Paracels.

After an extensive exploration program, the Philippines found the Nido oil field off the coast of Palawan Island, marking the first oil discovery in the Northwest Palawan Basin. The discovery came four years after the government passed the Oil Exploration and Development Act of 1972, which provided the legal basis for exploring and developing petroleum resources as Manila pushed for energy independence. Philippine Cities Service, Inc., the country’s first oil company, began drilling a well in the Nido oil field and launched commercial production in 1979, yielding 8.8 million barrels that year. 

China waged a short but bloody war with Vietnam, launching an offensive in response to Vietnam’s invasion and occupation of Cambodia in 1978, which ended the reign of the communist, Chinese-backed Khmer Rouge. The conflict marked the apex of tensions between Beijing and Hanoi, which were already running high after Vietnam established ties with the Soviet Union, China’s Cold War rival, the previous November. China had aided Vietnam in its wars against both France and the United States. Although both sides claimed victory, China withdrew from Vietnam after less than a month, having failed to coerce Vietnam to leave Cambodia. Roughly thirty thousand were killed in the short-lived conflict, which marked the beginning of many border disputes between Beijing and Hanoi and bolstered Vietnam’s lingering distrust of China.

After three decades of negotiations, the third and final United Nations Conference on the Law of the Sea, or UNCLOS, culminated in a resolution that defined the rights and responsibilities of nations in their use of surrounding waters based on exclusive economic zones and continental shelves. The measure came into force on November 14, 1994, a year after Guyana became the sixtieth nation to sign the treaty. UNCLOS does not address sovereignty issues related to the South and East China Seas, and its vague wording has prevented it from serving as a credible body of law in resolving territorial disputes. Although the United States recognizes UNCLOS as customary international law, it has yet to ratify the treaty—a move that would give Washington a greater platform from which it could advance its economic and strategic interests.

Malaysia occupied three Spratly Islands

After roughly a decade of relative calm in the South China Sea, China and Vietnam clashed on the Johnson Reef, marking China’s first armed conflict over the Spratly archipelago. The Chinese navy sank three Vietnamese vessels, killing seventy-four sailors in one of the most serious military confrontations in the South China Sea. The incident occured after Beijing, pursuing a more assertive stance in the area, established a physical presence on Fiery Cross Reef in the Spratlys in January 1987. In response, Vietnam occupied several reefs to monitor China’s moves. The incident unfolded amid Deng Xiaoping’s economic reforms of the 1980s, when Chinese economic activity began shifting to the coastal provinces, and maritime resources became increasingly prized as hydrocarbons were needed to sustain growth.

China invoked international law to expand its sea territorial to formalize its claim to both the Paracels and Spratlys

China passed the Law on the Territorial Sea and the Contiguous Zone, which laid claim to the entire South China Sea based on its historical right to the area dating from the Xia dynasty, which ruled between the twenty-first and sixteenth centuries BCE. The law employed more generous methods of territorial determination that would not necessarily be recognized and justified by UNCLOS, signed a decade earlier. The move was seen by some as a bid by China to obtain greater maritime security for itself, as Beijing was one of the most active countries at UNCLOS in attempting to obstruct the United States and Soviet Union’s efforts to secure freedom of navigation for warships.

Three Chinese naval vessels fought a ninety-minute battle with a Philippine navy gunboat near Capones Island in the Mischief Reef, part of the Spratly chain of islands claimed by Manila. The incident marked the first time China engaged in military confrontation with an ASEAN member other than Vietnam. The clash, which triggered a decline in Sino-Philippine relations, revived U.S.-Philippine military ties; soon after the incident, U.S. Navy SEALs conducted a joint exercise with their Philippine counterparts on Palawan Island, although Philippine President Fidel Ramos denied that this was connected to Manila’s row with Beijing. Tensions over the occupation subsided by midyear, when the Philippines and China signed a nonbinding code of conduct that called for a peaceful resolution to the territorial dispute and the promotion of confidence-building measures.

China and the ten ASEAN states reached an agreement in Phnom Penh on the ASEAN-China Declaration on the Conduct of Parties in the South China Sea, a code of conduct that sought to ease tensions and created guidelines for conflict resolution. The agreement came after six years of negotiations. Beijing had previously insisted on bilateral negotiations with claimants; China’s signing marks the first time it accepted a multilateral approach to the issue. Though the declaration fell short of a binding code of conduct, as the Philippines had sought, it signaled China’s recognition that such an agreement could work in its favor by limiting the risk of conflict in the area, which could involve the United States in the dispute.

China submitted its nine-dash line map to the United Nations, stating it “has indisputable sovereignty over the islands in South China Sea and the adjacent waters.” The Philippines, Vietnam, Malaysia and Indonesia protested the Chinese claim.

The International Energy Agency reported that China had surpassed the United States as the largest consumer of energy worldwide, consuming roughly 2.3 billion tons of total energy in 2009, approximately 4 percent more than the United States. China also became the second-largest consumer and net importer of oil, heightening the strategic importance of trade routes in the East and South China Seas for tanker shipments. The United States had been the world’s largest energy consumer since the early 1990s.

Exxon Mobil discovered oil off Vietnam’s coast in an area claimed by China. The discovery prompted the Philippine and Vietnamese leaders to agree to reinforce their maritime cooperation in the regions.

The US and the Philippines held a joint military exercise during a standoff over China’s illegal harvesting of coral and other sea life off of the Scarborough Shoal.

Vietnam passed a new maritime law claiming sovereignty over the Spratly and Paracel Islands; China raised the administrative status of the disputed islands to prefecture level.

China submitted claims to the East China Sea to the UN following the purchase of the Senkaku/Diaoyu Islands by the Japanese government.

Both the U.S. and China antagonized each other, with China announcing an air defence identification zone in the East China Sea surrounding the Senkaku/Diaoyou Islands. In response, the U.S. flew two jets through the surrounding airspace.

Joint US-Philippine military exercises took place near Scarborough Shoal.

Indonesia named the Natuna Sea as part of its maritime claim in the South China Sea.

Officials attending an ASEAN foreign ministers’ retreat agreed to work towards the conclusion of an effective Code of Conduct in the South China Sea based on a mutually-agreed timeline.

A US warship docked in Vietnam—the first such visit in more than 4 decades. 

US and Japanese naval forces took part in anti-submarine drills in South China Sea. Submarines are considered to be a key component in any future conflict in the region.

U.S. Navy destroyer carried out a “freedom of navigation” operation, coming within 12 nautical miles of an artificial island—Mischief Reef in the Spratly Islands—built by China in the South China Sea. The operation was an by US to counter China’s efforts to limit “freedom of navigation” in the strategic waters.

The Chinese navy launched a week-long series of live fire drills in the South China Sea. The drills involved an aircraft carrier and more than 40 vessels, and displayed a show of China’s military strength on the eve of the US’s own exercises in the region. This was the largest naval review in the country’s modern history.

US officials said they planned to send an aircraft carrier group into the Taiwan Strait in response to China’s recent efforts to impose its will over the contested area. The Chinese foreign ministry warned that this could jeopardize China-US peace in the region.

British warship the HMS Albion sailed through territorial Chinese waters near the Paracel Islands and was warned by the Chinese government to leave and immediately cease such “provocative actions.”

U.S. B-52 bombers flew over the East China Sea in a move Chinese officials called “provocative.” These actions fanned the flames of rising tensions between the two nations over trade tariffs.

Sailing near the disputed Spratly Islands, US Navy warship the USS Decatur nearly collided with a Chinese destroyer. The US claimed the Chinese ship was making unsafe, aggressive maneuvers that resulted in the near collision.

China and the nations of ASEAN held their first joint naval exercises, symbolizing the Southeast nations’ desire to improve trust with China.

The U.S. military said two of its warships sailed near Gaven and Johnson Reefs in the Spratly Islands. Beijing asserted the US “infringed upon Chinese sovereignty”, claimed the ships entered without permission and that the Chinese navy ordered them to leave.

The Philippines lodged a diplomatic protest against China after more than 100 Chinese fishing boats “swarmed” Pag-asa, also known as Thitu. The island is Philippine-administered and the second-largest naturally occurring landmass in the Spratly archipelago.

Two American aircraft carriers were deployed “in support of a free and open Indo-Pacific” while China conducted military drills nearby.

U.S. Secretary of State Mike Pompeo declared China’s claims “completely unlawful”. In response, the Chinese embassy in the US accused the US of “inciting confrontation”. 

Reports on the South China Sea Dispute

For more information and the latest developments on the South China Sea Dispute, please see the list below for a collection of reports written by our correspondents.

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