Dr. Heiko Herold**

Taiwan’s maritime security is shaped by its dependence on maritime trade, its proximity to an increasingly assertive and aggressive China, and the need to protect its critical sea lines of communication. This article focuses on the core aspects of Taiwan’s maritime security by outlining its strategic importance, analyzing the nature of maritime threats posed by China, identifying Taiwan’s key vulnerabilities at sea, and assessing the measures Taiwan is taking to deter and counter Chinese aggression in the maritime domain.

Why does Taiwan’s maritime security matter? It is of great importance because it protects the sovereignty of a thriving democracy at a strategic crossroads, it safeguards vital sea lanes and submarine infrastructure crucial for global trade and semiconductor supply chains, and it helps maintain peace and stability in the Indo-Pacific region in the face of China’s continued military pressure and gray-zone aggressions. This security effort addresses a wide range of challenges including naval intimidation and the risk of blockades, cyber warfare, legal disputes, and coercive gray-zone tactics designed to undermine Taiwan’s control over its maritime zones and threaten its vital ports, sea lines of communication, and critical seabed infrastructure. It also strengthens Taiwan’s role as a crucial pillar for maintaining the regional order and preventing disruptions to the global economy.

Taiwan holds a crucial strategic location in the Indo-Pacific region due to its position within the “first island chain,” which stretches from Japan through Taiwan to the Philippines and down to Borneo. This island chain is key to controlling access between the East and South China Seas and beyond to the Pacific and Indian Oceans. Taiwan functions as a maritime gateway, controlling vital sea lanes essential for global trade and military logistics, particularly connecting Northeast Asia with the markets of Europe and the Middle East. Taiwan’s geographic significance extends to its relations with its neighbors, making the island a central point in the regional security dynamics between China, the United States, Japan, and other Indo-Pacific powers. The island’s location limits China’s access to the Pacific Ocean, thereby impacting its maritime expansion ambitions and strategic deterrence capabilities, especially regarding submarine operations and ballistic missile forces.

The waters surrounding Taiwan are a focal point of strategic and geopolitical tensions. They encompass the East China Sea to the north, the Taiwan Strait to the west, the South China Sea to the south, and the Pacific Ocean to the east. The Taiwan Strait, a vital international waterway connecting the East and South China Seas, is a crucial maritime route for trade and military movements. China claims it as part of its internal waters, but this position has no legal basis; it contradicts international law and violates the United Nations Convention on the Law of the Sea, or UNCLOS, including provisions guaranteeing freedom of navigation. China’s aggressive maritime claims extend throughout these and adjoining waters, especially under the umbrella of the expansive and internationally disputed “ten-dash line”, which includes nearly 90% of the South China Sea and overlaps with territorial claims by Taiwan and several Southeast Asian nations. This claim is also illegal under international law. In 2016, an UNCLOS arbitration tribunal definitively rejected China’s fabricated historical claims to these waters, ruling that they lacked any legal or factual basis. [1] Nevertheless, China is pursuing these claims through gray-zone warfare, military presence, lawfare, and land reclamation projects for military purposes to consolidate its control and restrict access to the South China Sea. In response, the United States and regional actors such as the Philippines and Japan are deepening their naval and other military cooperation, for example, through defense pacts and recent naval exercises in the South China Sea, to strengthen joint maritime security and counter China’s hegemonic power ambitions. These enhanced partnerships reflect growing concerns about China’s increasing influence and support freedom of navigation and regional security in these disputed waters.

China is posing a growing challenge to Taiwan through explicit threats of forcible annexation, misleadingly framed as “reunification,” even though Taiwan has never been part of the People’s Republic of China. Beijing’s strategy aims to conquer Taiwan without firing a shot, that is through gray-zone tactics designed to weaken its defenses, normalize border violations, deplete resources, and force Taiwan to surrender through economic strangulation, disinformation, and psychological pressure. In the maritime domain, these gray-zone operations include severing submarine cables vital to Taiwan’s economy and military, cyberattacks on critical infrastructure, and the Chinese Coast Guard’s alleged “law-enforcement” in waters around Taiwan’s outlying islands.

Chinese forces regularly intrude into Taiwan’s maritime borders as well as its air defense identification zone beyond the median line with hundreds of incursions per month using military aircraft, naval vessels, and drones. The aim of these actions is to weaken Taiwan’s reactive capabilities and test its response times. The People’s Liberation Army regularly conducts large-scale exercises around Taiwan, practicing joint blockade operations, amphibious landings, and missile strikes to refine invasion tactics and signal a readiness for rapid escalation. Underpinning these efforts is China’s rapid naval expansion—now the world’s largest fleet by number, including aircraft carriers and nuclear submarines—and the comprehensive modernization of its air force, focusing on stealth fighters, long-range bombers, unmanned aerial systems and drones. All of this is designed to achieve naval and air superiority in a potential conflict and deter U.S. intervention.

What are Taiwan’s key vulnerabilities in the maritime security domain that China could exploit in a crisis or wartime scenario? As a densely populated island with limited natural resources, it is heavily dependent on maritime imports, particularly regarding energy, food, raw materials, chemicals, and military equipment. The most significant maritime export dependencies are concentrated on high-value industrial goods, particularly electronics, which make up over 40 percent of exports.[2] Most of Taiwan’s imports and exports by sea move through a small number of major ports such as Kaohsiung, Taichung and Taipei, which together handle tens of millions of containers and hundreds of billions of U.S. dollars in trade each year. This intense port activity is large even relative to Taiwan’s overall GDP, underscoring how central seaborne trade is to its economy.[3] Therefore keeping access to regional and global sea lanes is framed as “critical to national survival.”[4]

Energy is one of Taiwan’s sharpest vulnerabilities, since the island has virtually no domestic fossil fuel production and relies almost entirely on seaborne imports of oil, coal, and especially liquefied natural gas to power its industries and cities. Any sustained disruption to shipping routes or port operations would therefore quickly affect electricity generation, industrial output, and living standards.

Taiwan also relies on maritime imports for a significant portion of its food supply, reflecting a high degree of dependency on global markets for agricultural and food products. In recent years, its food self-sufficiency rate has dropped to roughly 30 percent. While Taiwan maintains high self-sufficiency in some sectors—such as rice—its reliance on maritime imports is especially acute for meat, animal feed, seafood, and high-value processed foods. Taiwan has stockpiled food supplies for several months. However, any disruption to sea lanes would quickly impact the island’s ability to secure a wide variety of food products, underscoring the close link between its food security and the stability of maritime trade routes.[5]

Taiwan also depends heavily on seaborne deliveries for major military platforms, spare parts, and advanced components, because most of its high-end defense equipment is imported, above all from the United States. Complex systems such as fighter aircraft, air-defense missiles, precision-guided munitions, and many critical subsystems for indigenous weapons programs all arrive by ship or rely on maritime Taiwan’s F-16, C-130, and Indigenous Defense Fighter fleets.[6] Nonetheless, any blockade or serious disruption of commercial shipping could quickly affect Taiwan’s ability to sustain operations, replace losses, and keep its armed forces supplied over time.

Taiwan’s export model also ties its prosperity to secure sea lanes, particularly for semiconductors and other electronics that dominate its trade profile. Taiwanese companies produce the vast majority of the world’s most advanced chips and many other electronics, and lots of these components leave the island by ship to feed global manufacturing and digital infrastructure. For this reason, a naval blockade or war over Taiwan would not only affect the island’s economy but would also have repercussions for global supply chains.

Taiwan counters Chinese aggression through what once was called “Overall Defense Concept,” a doctrine emphasizing “agile response capabilities and whole-of-society defense resilience,” as stated in the 2025 Quadrennial Defense Review.[7] Its core objective is to build a force that can foil the enemy by employing asymmetric warfare, mobility, and denial strategies to survive initial assaults and impose high costs on invaders. Military modernization drives this effort, with President Lai Ching-te announcing in his 2025 National Day speech a special budget to push defense spending above 3% of GDP immediately and to 5% by 2030, funding the indigenous“T-Dome” multi-layered air defense system for “high-level detection and effective interception,” alongside Hai Kun submarines, Tien Kung III missiles, and mass drone production.[8] The 2025 National Defense Report reinforces “layered deterrence” and “resilient defense,” integrating intelligence, surveillance and reconnaissance assets like radars, unmanned aerial vehicles, and reserves for “multi-domain denial,” with the annual Han Kuang exercise simulating a Chinese blockade and invasion and practicing rapid mobilization.[9]

Taiwan bolsters its maritime domain awareness and counters Chinese claims through expanding international cooperation, hosting forums like the 2025 Taiwan International Ocean Forum where President Lai emphasized working “with democratic partners throughout the world in a maritime spirit of freedom and openness to contribute to ocean governance and jointly ensure maritime security.”[10] The U.S. National Defense Authorization Act for Fiscal Year 2026 authorizes deepened U.S. Coast Guard training with Taiwan’s Coast Guard Administration on maritime security and law enforcement and directs the U.S. Department of War “to engage with Taiwan to develop a joint program to co-develop and co-produce uncrewed and counter-uncrewed capabilities.”[11] Taiwan pursues joint patrols and intelligence-sharing with Japan and the Philippines amid South China Sea tensions, and invests in unmanned surface vessels and AI surveillance according to the 2025 National Ocean Policy White Paper to address gray-zone threats like illegal fishing and seabed infrastructure sabotage, demonstrating a shift from unilateral defense to multilateral deterrence.[12]

In practice, Taiwan intercepted and charged the captain of the Togolese-flagged cargo vessel “Hong Tai 58,” crewed by Chinese nationals, in February 2025 for deliberately severing a submarine cable off its southwest coast—the first such prosecution— arrested the crew, escorted the ship for investigation, and increased coast guard patrols to counter gray-zone sabotage.[13] Taiwan continuously monitors incursions by People Liberation Army aircraft, deploying combat air patrol fighters such as F-16s for identification and interception, but these are carefully calibrated responses to avoid escalation. Coastal missile systems and naval assets also track and prepare to counter threats. Taiwan has also proposed forming a “National Defense Innovation Task Force” as part of its 2025 Quadrennial Defense Review to prioritize areas like unmanned systems, counter-unmanned systems, and AI applications, including for its naval forces.[14]

The question of how real a Chinese attack on Taiwan is in the near future is a concern for politicians, military leaders, and analysts worldwide. Numerous warnings from the U.S., Japan, Taiwan itself, and other partner countries underscore the heightened risk in the coming years. The year 2027 is repeatedly mentioned, a symbolically and politically significant date: the 100th anniversary of the People’s Liberation Army and a target year by which China intends to have fully modernized its armed forces. According to U.S. intelligence estimates, “Xi has ordered his military to be ready for a military takeover of Taiwan by 2027.”[15] President Xi Jinping has repeatedly stated his intention to resolve the “Taiwan question” during his lifetime. Unlike Deng Xiaoping, he understands so-called “reunification” not as a long-term process, but as a political legacy. This adds further political pressure to the issue.

China has been intensifying its military preparations for years, some visibly, some covertly. These include the large-scale modernization of its navy, the gradual maritime encirclement of Taiwan, extensive hybrid operations, and increasingly realistic exercises simulating blockades and invasion scenarios. Hybrid warfare is already in full swing, with submarine cable sabotage, disinformation, cyberattacks, and economic pressure. The military refers to this as shaping the battlefield.

The situation is also geopolitically dangerous due to a changed strategic environment: Many observers consider a Chinese attack on Taiwan during Donald Trump’s second term in office realistic. From Beijing’s perspective, a U.S. president who unsettles allies and questions multilateral structures could reduce the costs of a Chinese military intervention. Xi Jinping has repeatedly and publicly affirmed China’s commitment to peace. We should not be fooled. China’s intense hybrid war against Taiwan and its unmistakable preparations for a kinetic war tell a different story.

At the same time, many experts emphasize that China is not yet ready for a large-scale military operation against Taiwan. Added to this are economic challenges, domestic political pressure, and uncertainty about the reactions of the U.S. and its partners. The so-called “four-front argument,” which was rolled out in Chinese propaganda in 2023, illustrates the geopolitical complexity that would make a full-scale war risky for China. According to this argument, China faces the threat of war on four fronts simultaneously: Taiwan, the South China Sea, the border with India, and, particularly noteworthy, Korea. While the four-front argument was intended to appease war hawks in China, it also underscores that, according to Chinese military planners, a war over Taiwan would most likely not be a limited war.[16]

However, we cannot rely on China only daring to attack Taiwan when its military is supposedly ready for it. Furthermore, an attack would not necessarily have to begin with a full-scale invasion. More likely are escalating preliminary stages: for example, the blockade of individual ports, the disruption of critical sea lines of communication, and military “test attacks” on Taiwanese offshore islands such as Pratas, Taiping, Kinmen, or Matsu.

How can an attack be prevented? The most important factor is deterrence, specifically a deterrence that, from a Chinese perspective, is so costly that it would threaten the very core of the Communist Party. What Xi and party leadership fear most is not just a military fiasco, but an attack that ends in chaos and endangers the regime itself. This requires three core elements:

1. Taiwan needs strong and reliable alliances, above all with the United States and Japan, complemented by a deepening cooperation with Australia, the Philippines, and key European partners.

2. Maximum resilience for Taiwan: militarily, economically, digitally, and societally, to withstand and recover from sustained pressure or disruption.

3. Taiwan needs credible defense capabilities including asymmetric systems, multi-domain denial, robust maritime defenses, protection of critical infrastructure, and high mobilization capacity.

Finally, I would like to address one last important point: We must not consider the Taiwan issue in isolation. We are already in the midst of a systemic rivalry between autocracies and democracies. Taiwan, Ukraine, and Israel are fighting on the front lines. The hybrid war waged by the autocracies is directed against the global West, and it is continuously intensifying. Further kinetic wars are looming on the horizon, and it is unclear whether they can be prevented. If the autocrats have their way, the international rules-based order will be replaced by a multipolar world order, which means nothing other than exclusive spheres of influence for a few major powers. In the Indo-Pacific, this means: China wants to take control of Taiwan and push the Americans out of the Pacific in order to dominate the region. But the Chinese Communist Party is already thinking further ahead and dreams of a Sinocentric world order. One remark Xi Jinping made to Vladimir Putin in March 2023 was particularly revealing, as it highlighted both the scale of the current global upheavals and the deliberate intention behind them: “Right now there are changes –the likes of which we haven’t seen for 100 years – and we are the ones driving these changes together.”[17]

Therefore, from a European perspective, it is in our own best interest, not only for economic but above all for geostrategic reasons, to do everything possible to support Taiwan in its defensive measures against the increasingly aggressive and belligerent People’s Republic of China with our democratic allies worldwide and to prevent a Chinese takeover of the island republic.