China’s interests in the South China Sea are profoundly commercial and economic, not merely military or nationalist. The sea functions as one of the central arteries of China’s economy and global position. Beijing views control, influence, or at least secure access to the region as vital to national survival and long-term development.

The South China Sea as a Strategic Economic Corridor. Roughly one-third of global maritime trade passes through the South China Sea (SCS), including enormous volumes of container shipping, energy imports, bulk commodities, and manufactured exports. For China specifically, the sea links China’s industrial east coast, Southeast Asian markets, the Indian Ocean, the Middle East, Europe, Africa and the United States. Chinese ports such as Port of Shanghai, Port of Shenzhen, and Port of Guangzhou depend heavily on uninterrupted maritime access through these waters. A disruption in the SCS could severely affect the exports of Chinese manufactured goods, imports of raw materials, and China’s supply chains.

Maritime trade in the South China Sea can be described by any number of measures. Its importance can be measured in a variety of ways: total trade value, shipping volume, energy flows, container traffic, and its role in global supply chains. The most widely cited estimate is that roughly $3–5 trillion in global trade passes through the SCS annually. That represents approximately 25% of global marine trade. Roughly one-third of global maritime crude oil trade passes through these waters. East Asia is the manufacturing center of the global economy and the SCS is central to containerized trade. Major shipping companies route vessels through the SCS because it is the shortest and most efficient path from manufacturing centers to delivery ports abroad. 

China’s economy is particularly dependent on these routes because China is the world’s largest exporter, it imports massive energy supplies, and much of its coastal industrial economy faces the South China Sea. Chinese strategic planners worry about blockade risks, foreign naval control, and vulnerability at maritime chokepoints – especially the Malacca Straits, the southwest entrance to the South China Sea.

Energy Security: Oil and LNG Imports. One of China’s greatest vulnerabilities is energy dependence. China imports massive amounts of crude oil, liquefied natural gas (LNG), and other energy products from the Persian Gulf, Africa, and elsewhere in the Indian Ocean region. Much of this energy passes through the Strait of Malacca, then across the South China Sea, and onward to Chinese ports. Chinese strategists often refer to this vulnerability as the “Malacca Dilemma,” the fear that in a crisis, especially involving the United States, these sea lanes could be interdicted or blockaded. This concern drives several Chinese policies including naval modernization, artificial island construction, maritime patrol expansion, diversification of pipelines, and the Belt and Road Initiative.

Oil and Gas Resources Within the South China Sea. The South China Sea itself is believed to contain significant oil reserves, very large natural gas reserves, and rich seabed resources. Estimates vary widely because much of the region remains underexplored, but China sees these potential reserves as strategically important. China’s state energy firms, including China National Offshore Oil Corporation (CNOOC), have pursued offshore drilling, seismic surveys, and joint development proposals. Disputes emerge because Vietnam, the Philippines, Malaysia, and Brunei also claim many of the same waters and offshore blocks.

Fisheries and Food Security

The South China Sea contains some of the world’s richest fishing grounds. Fish are commercially important to China because seafood demand is enormous, coastal populations have long depended on fishing, and food security remains a strategic concern. Chinese fishing fleets operate extensively in disputed waters. Fishing vessels also serve secondary purposes: reinforcing Chinese presence, supporting maritime claims, and sometimes operating alongside the Chinese maritime militia.

Precise estimates of annual fish extraction are difficult because the SCS is heavily overfished, illegal and unreported fishing is widespread, and countries often underreport or distort catch data. Some estimates suggest over half the world’s fishing vessels operate in the broader South China Sea region. But the best academic and fisheries reconstructions provide reasonably credible estimates.  Most estimates center on 10 million metric tons per year of fish caught in the SCS. China is estimated to take 35-50% of the total catch which is not surprising since China possesses (by far) the world’s largest fishing fleet, including coastal fleets, distant-water fleets, and maritime militia-associated vessels. 

China is the world’s largest seafood consumer and growing middle-class demand has intensified fishing pressure. It must also be remembered that fishing activity is not only economic, but reinforces maritime claims, presence around disputed reefs, and gray-zone operations. As such, the Chinese fishing fleet is highly subsidized because of its importance to China’s economy. 

Fish are not a marginal issue in the SCS dispute. For China, fisheries involve food security, employment, maritime sovereignty claims, and regional influence. Some analysts argue that fisheries are one of the most immediate drivers of day-to-day confrontation in disputed waters – more so than oil. This is because studies indicate fish stocks in the SCS have declined by 70–95% since the 1950s, catch rates have fallen dramatically, and fleets increasingly catch smaller and younger fish lower on the food chain. China and bordering nations, all of which historically and culturally have fish as a major source of dietary protein, are chasing an increasingly diminishing commodity.

China has been aggressively intruding into waters and maritime zones that the Philippines claims under international law, particularly within the Philippine Exclusive Economic Zone (EEZ) in the SCS. Much of the friction occurs in waters west of the Philippine island of Palawan, especially around Second Thomas Shoal, Scarborough Shoal, Mischief Reef and Reed Bank. These areas fall within 200 nautical miles of the Philippines and are therefore claimed by Manila as part of its EEZ under the United Nations Convention on the Law of the Sea. Philippine fishermen have repeatedly reported being blocked from traditional fishing grounds, harassment by Chinese coast guard vessels (which are armed with 5-inch guns and automatic weapons), water cannon incidents, confiscation of catches, and dangerous maneuvering at sea. China coast guard and maritime militia vessels are constructed with reinforced bows capable of – not full on ramming – but shall we say quite aggressive nudging.

Maritime militia vessels disguised as fishing boats and PLA Coast Guard vessels are used to assert Chinese claims, maintain constant presence, pressure rival claimants, while avoiding overt naval warfare. The Philippines and its allies characterize many of these tactics as “gray-zone coercion,” aggressive pressure below the threshold of armed conflict.

Trade With Southeast Asia. The South China Sea is also the maritime bridge connecting China to the Association of Southeast Asian Nations (ASEAN) economies. ASEAN is one of China’s largest trading partners accounting for 20% of trade with China. Goods moving through the region include electronics, machinery, semiconductors, consumer goods, agricultural commodities, and industrial inputs. Any instability in these waters threatens Chinese exports, regional manufacturing networks, and supply-chain integration.

Undersea Infrastructure and Communications. Less visible but increasingly important are submarine communication cables, offshore infrastructure, and digital trade routes. The South China Sea contains major undersea fiber-optic cable systems connecting East Asia to the broader world economy. Control or monitoring of maritime zones can therefore have implications beyond shipping to include telecommunications, internet traffic, financial systems, and digital commerce.

The SCS marine floor has the highest concentration of marine fiber optic cables. These cables carry financial transactions, cloud computing traffic, military communications, commercial internet traffic, and industrial data. For China, they support export industries, global manufacturing networks, e-commerce, artificial intelligence infrastructure, and digital connectivity under the Belt and Road Initiative.  The SCS infrastructure forms the hub that connects China and East Asia with Singapore, India, the Middle East, Europe, and Africa. It is part of China’s “Digital Silk Road” initiative.

The geography of the SCS makes it difficult to avoid. Nearly all East Asian digital traffic heading westward toward Europe or the Indian Ocean passes through cables in these waters. This creates both opportunity and vulnerability for China. Chinese strategists worry about cable sabotage, surveillance, bottlenecks, and wartime disruption. As a result, China has pursued redundant cable routes, alternate land corridors, and Arctic communications concepts, yet 95% of China’s extra-territorial communication still passes through these cables.

Strategic Economic Buffering. China’s island-building campaign has economic as well as military dimensions. Artificial islands allow China to support coast guard and maritime enforcement activity, monitor shipping, sustain fishing fleets, protect energy exploration, and reinforce administrative control over contested waters. Beijing argues these activities secure lawful commercial interests; critics view them as coercive attempts to dominate international waters.

The Broader Chinese Perspective. From Beijing’s viewpoint, the South China Sea is not a distant frontier. It is viewed as 

• a near-seas defensive zone,
• an economic and food security lifeline,
• an energy transit corridor,
• and a gateway to China’s continued rise as a global power.

Many Chinese strategists believe that if hostile powers controlled these waters, China’s economy, trade, energy supply, and geopolitical autonomy could all be placed at risk. That perception helps explain why the South China Sea occupies such a central place in Chinese national strategy even beyond the military dimension.