The South China Sea is one of the world’s most economically important waterways and increasingly one of Asia’s biggest flashpoints.
Covering 3.5 million square kilometers (1.35 million square miles), the ocean is a busy shipping lane through which trillions of dollars’ worth of trade pass every year, and is also rich in fish and thought to contain significant oil and gas reserves.
But the sea and the various reefs, islands and rocks within it have been the subject of a fierce, long-standing territorial dispute. China claims most of the area as its own, ignoring a 2016 ruling by the International Court of Justice in The Hague that found its broad claims had no legal basis. Since 2013, China has carried out extensive construction work, building artificial islands for military use in the area. Other countries have overlapping claims, including the Philippines, a U.S. treaty ally that has repeatedly accused Chinese vessels of dangerous and aggressive behavior at sea, and Vietnam, which is currently engaged in rapid island construction. Malaysia, Brunei and Taiwan also have competing claims.
Below is a comprehensive list of the region’s major land formations, their rulers, the conflicts, and why it’s important.
Second Thomas Scholl
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position: Within the Philippine Exclusive Economic Zone (EEZ)*, 194 km (105 nautical miles) off the Philippine island of Palawan.
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Occupied byThe Philippines is effectively under a blockade by China, analysts say.
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Claimant: Philippines, China, Taiwan, Vietnam.
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What’s there?The BRP Sierra Madre, a rusting World War II-era ship, was deliberately run aground by the Philippines in 1999 and now serves as an unlikely military outpost.
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Why is this important?For the Philippines, Sierra Madre is a symbol of the country’s defiance against Chinese expansionism. But the island is in disrepair, and some analysts warn it may be on the verge of collapse. China has repeatedly blocked Philippine resupply missions to the island and has tried to block the delivery of construction materials needed to strengthen the island’s structures.
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Recent conflicts: Since February 2023, the Philippines has accused China of eight aggressive and dangerous acts around Second Thomas Shoal, including firing military lasers and water cannons at Philippine Coast Guard crews and ramming vessels. Most recently, in June 2024, the Philippines accused Chinese Coast Guard vessels of ramming, towing, and knifeing Philippine vessels, looting disassembled firearms, destroying communication and navigational equipment, and confiscating crew members’ mobile phones. One naval officer lost a thumb in the incident.
Scarborough Shoal
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position: Located within the Philippine EEZ, 230 km (124 nautical miles) from the Philippine island of Luzon.
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Occupied by: The Chinese coast guard has had a continuous presence in the area since 2012, when it took control of the area after a two-month standoff with Philippine ships.
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Claimant: Philippines, China, Taiwan.
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What’s in there: China has not constructed any structures in these shallow waters, unlike other features it controls in the South China Sea.
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Why is this important?The occupation of the rich fishing grounds of Scarborough Shoal in 2012 was one of the reasons that prompted the Philippine government to refer the dispute to international arbitration. The court ruled in favor of the Philippines and found China’s sweeping territorial claims in the South China Sea invalid.
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Recent conflicts: In February, the Philippine Coast Guard accused the Chinese Coast Guard of dangerous maneuvers to harass its vessels near Scarborough Shoal. China has been accused of setting up floating fences to block Philippine ships’ access to the area and swarming there to harass Philippine fishing boats.
Thitu Island
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explanation: An island less than a mile long.
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position: 426km (It is located approximately 230 nautical miles west of Palawan province in the Philippines.
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Occupied by: Philippines.
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Claimant: Philippines, Vietnam, Taiwan, China.
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What’s in there: Thitu is home to about 250 people and has internet and mobile phone access, an airstrip, a port, a school, a gymnasium and a typhoon shelter.
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Why is this important?: It is the largest Philippine-administered island in the Spratly Islands, and the Philippine government is encouraging fishing communities to relocate there. China’s Coast Guard and maritime militia regularly patrol the surrounding waters.
Sabina Shawl
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explanation: An atoll 22 km (12 nautical miles) long.
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position: Located within the Philippine EEZ, 139 km (75 nautical miles) off the coast of Palawan Island, Philippines.
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Occupied by: Vacant
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Claimant: Philippines, China, Taiwan
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What’s in there: The Philippine Coast Guard’s most advanced vessel, the 97-metre Teresa Magbanua, has been stationed in the area since April to monitor Chinese reclamation activities. China, which denies any reclamation activities, has responded by dispatching a 165-metre, 12,000-ton coast guard vessel nicknamed “Monster” for its size. The vessel has been stationed in the area since July 3 and is located less than half a mile from the Teresa Magbanua.
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Why is this important: Sabina Shoal is close to Reed Bank, which is believed to be rich in oil and gas, and also serves as a staging point for ships carrying out resupply missions to the Philippine military at Second Thomas Shoal.
China’s “Big Three” in the Spratly Islands: Mischief Reef, Subi Reef, and Fiery Cross
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explanation: The militarized reefs have been converted into artificial islands and reclaimed areas of 558 hectares (1,379 acres), 395 hectares (976 acres), and 274 hectares (677 acres), respectively.
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position: It is located in the Spratly Islands. A UN tribunal in 2016 ruled that Mischief Reef is part of the Philippines’ EEZ because it was underwater before China built up land on it.
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Claimant: China, Taiwan, Philippines, Vietnam
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Occupied by: China
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What’s in there: The reefs are equipped with anti-ship and anti-aircraft missile systems, lasers and jamming devices, and fighter jets, the United States says.. Underground storage tunnels were also constructed.
Lead Bank
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explanation: Lead Bank Isolated undersea volcano
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position: Reed Bank is located about 157 km (85 nautical miles) off the coast of Palawan and is within the Philippine EEZ.
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Claimant: Philippines, China, Taiwan.
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What’s in there: The Philippines has accused China of causing severe damage to the marine environment and coral at Iroquois Reef, at the southern end of the Reed Bank, in an area believed to be rich in oil and gas. It has said it is considering legal action.
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Why is this important?The site is crucial for the Philippines, which is facing a looming energy crisis as the Malampaya gas field, which provides a fifth of the electricity on the country’s main island of Luzon, is nearly depleted. Exploration has been halted for years because of tensions with China.
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Recent conflictsChina’s maritime militia isTheft by software occupationBoats gather intermittently at Iroquois Reef to form a floating outpost, which is also patrolled by the China Coast Guard.
Paracel Islands
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explanation: An archipelago of over 130 coral islands, shoals and reefs
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position: It is located in the northern South China Sea, about 370 kilometers (200 nautical miles) southeast of China’s Hainan Province.
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Claimant: China, Vietnam, Taiwan
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Occupied by: China
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What’s in there: China has 20 bases in the Paracel Islands These are critical for surveillance in the South China Sea. These waters are equipped with protected ports and helipads that can accommodate numerous naval and civilian vessels. Woody Island, the largest of the Paracels, is home to at least 1,000 Chinese nationals and is equipped with an airstrip, hangars and an HQ-9 surface-to-air missile battery, according to the Asia Maritime Transparency Initiative.
Whitsun Reef
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explanation: A V-shaped coral reef in the Spratly Islands.
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positionThe location is within the Philippines’ EEZ, approximately 324 km (175 nautical miles) off the coast of Palawan Island.
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Claimant: China, Philippines, Vietnam
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Occupied by: Vacancy
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What’s in there: Searight, who monitors the waters, said maritime militia vessels have come together to form floating outposts in the region and maintain a continuous presence, but only scale back their presence during the Lunar New Year.
Vanguard Bank
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explanation: A submerged terrain containing three Vietnamese military outposts.
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position: Within Vietnam’s EEZ
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Claimant: Vietnam, China, Taiwan
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Occupied by: Vietnam
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What’s there?: Oil and gas fields off the coast of Vietnam, where China has been accused of conducting aggressive and intrusive patrols.
Luconia Shoals
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explanation A collection of coral reef plateaus and small atolls.
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position: The southernmost tip of the Spratly Islands, within Malaysia’s EEZ.
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Claimant: China, Malaysia and Taiwan.
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Occupied by: It is managed by Malaysia.
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What’s in there: Oil and gas fields off the coast of Malaysia, where China has been accused of conducting aggressive and intrusive patrols.
Bark Canada Reef
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explanation: A narrow reef in the southern Spratly Islands has nearly doubled in size from 96 hectares (238 acres) to 167 hectares (412 acres) in the past six months as Vietnam accelerates the expansion of its base, according to AMTI.
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position: It lies more than 370 km (200 nautical miles) west of the islands of Borneo and Palawan.
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Occupied by: Vietnam.
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ClaimantBurke Canada Reef is claimed by China, Malaysia, the Philippines and Vietnam.
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Why is this important?Burke Reef is currently the only Vietnamese base with the potential to build a 3,000-meter runway suitable for large military aircraft. Vietnam has been rapidly expanding its reach in the South China Sea, claiming almost as much new land so far this year as it did in the previous two years combined, according to the AMTI study.
*Exclusive Economic Zone – An area of the ocean extending 200 nautical miles (370 km) from a country’s coastline where a country has special rights to develop resources and carry out construction.
