Taiwan and the South China Sea: Navigating Islands, Boundaries, and Sovereignty

The South China Sea is one of the world's most critical maritime chokepoints, serving as a conduit for over a third of global shipping. It is also a region of intense geopolitical friction, characterized by overlapping territorial claims, vast energy reserves, and rich fishing grounds. While the disputes primarily involve China, Vietnam, the Philippines, Malaysia, and Brunei, the role of the Republic of China (ROC), commonly known as Taiwan, introduces a distinct and often overlooked dimension to the conflict. Taiwan’s governance of key islands, its historical claims rooted in the post-World War II order, and its ambiguous international status create a complex interplay of law, history, and power politics. This article examines Taiwan’s specific claims, the maritime features it controls, the legal frameworks involved, and the broader geopolitical dynamics that shape its role in the South China Sea.

Historical Foundations of the ROC's Maritime Claims

The foundation of the Republic of China's claims in the South China Sea dates back to the 1940s. Following the end of World War II, the ROC, under the Kuomintang (KMT) government, was one of the Allied powers. In 1946, the ROC dispatched naval vessels to reclaim the Pratas and Spratly Islands from Japanese occupation. This act of reclamation was accompanied by the formal establishment of garrisons and the erection of sovereignty markers. In 1947, the ROC government published a "Map of the South China Sea Islands," which included the infamous "U-shaped" or "Eleven-Dash Line" representing its territorial claims within the South China Sea. This line was later reduced to the "Nine-Dash Line" after the PRC gained control of the Chinese mainland.

When the KMT retreated to Taiwan in 1949, the administrative continuity over these distant outposts remained intact. The ROC on Taiwan continued to garrison the Pratas Islands and Taiping Island (the largest natural island in the Spratly group) throughout the following decades. This physical presence forms the bedrock of Taiwan’s claim to be a legitimate sovereign participant in the disputes, arguing a continuous and effective administration dating back to the immediate post-war period. The PRC, however, since its founding, has claimed to be the sole legitimate government of all of China, including Taiwan, and therefore views the ROC’s claims as a matter of internal Chinese politics rather than a separate international dispute.

The "U-shaped line" remains a central, yet legally ambiguous, element of both the PRC and ROC claims. For decades, neither side fully clarified whether the line represented a claim of historic sovereignty over the land features within it, or a claim over the maritime resources and waters themselves. Taiwan’s official position has historically been more cautious than Beijing's. While the ROC maintains that the South China Sea islands are "inherently" part of Chinese territory, it has shown a greater willingness to engage with international law, particularly the United Nations Convention on the Law of the Sea (UNCLOS), which it recently signaled its intention to adhere to. This nuanced stance places Taiwan in a unique position, straddling the line between its historical narrative and the modern demands of international maritime law.

The Inventory of ROC-Held Features in the South China Sea

Taiwan's territorial presence in the South China Sea is limited but strategically significant. It controls two sets of features: the Pratas Islands and Taiping Island in the Spratly Islands. It also maintains historical claims over other features currently occupied by other nations.

The Pratas Islands (Dongsha Qundao)

The Pratas Islands are located in the northern part of the South China Sea, roughly 340 kilometers southwest of Kaohsiung. The only feature in this group is Dongsha Island, a small coral atoll. The ROC maintains a military garrison and a Coast Guard administration on the island, which also houses a weather station and a national park. Due to its proximity to Taiwan, the Pratas are generally considered the most firmly held of Taiwan’s South China Sea possessions. However, the island's low elevation and lack of fresh water make it vulnerable to environmental changes and logistical challenges.

The Spratly Islands (Nansha Qundao) and Taiping Island

The most significant of Taiwan's holdings in the South China Sea is Taiping Island (Itu Aba), the largest naturally occurring island in the Spratly archipelago. At approximately 0.5 square kilometers, Taiping Island is a unique feature in a sea of mostly submerged reefs and artificial structures. It possesses a natural freshwater lens, which is exceptionally rare in the Spratlys, making it capable of supporting a permanent human presence. The ROC has significantly upgraded the island's infrastructure in recent years, including the construction of an airstrip capable of handling C-130 transport aircraft, a hospital, a solar power plant, and a lighthouse for civilian maritime safety.

Taipei frames these developments as a commitment to providing a "peaceful and humanitarian" role in the region. The airstrip and hospital are frequently highlighted as resources for international search and rescue operations and humanitarian assistance. This stands in stark contrast to the large-scale land reclamation and militarization activities conducted by China, Vietnam, and Malaysia on other features in the Spratlys. Despite being subject to the same disputes, Taiwan’s approach on Taiping Island offers a potential alternative model for coexistence in the region, though its effectiveness is limited by Taiwan's diplomatic isolation and the PRC's overarching claims.

Claimed but Not Held: Scarborough Shoal and the Paracels

While Taiwan does not currently occupy Scarborough Shoal (Huangyan Island) or the Paracel Islands (Xisha Qundao), it continues to assert historical sovereignty over them. Scarborough Shoal, located west of the Philippines, has been under effective control of the PRC since a tense standoff with the Philippines in 2012. The Paracel Islands have been under PRC control since a brief military conflict with the Republic of Vietnam in 1974. Taiwan’s claims to these features remain formally in place, but the ROC has no means to enforce them.

This creates a curious dynamic where the PRC actively administers and militarizes these features, while the ROC, which claims to represent the same "Chinese" sovereignty, can only issue verbal protests. The PRC’s actions on Scarborough Shoal and the Paracels are, in effect, done in the name of a China that theoretically includes Taiwan, leaving the ROC in a position of being a claimant that has lost control of its claimed territories to a rival government with a superior military capability.

  • Pratas Islands: Under ROC control; used for military, weather, and environmental monitoring.
  • Spratly Islands: ROC controls Taiping Island (Itu Aba), the largest natural island.
  • Scarborough Shoal: Controlled by PRC; claimed by both PRC and ROC.
  • Paracel Islands: Controlled by PRC; historically claimed by ROC.

Maritime Boundaries and the Exclusive Economic Zone Challenge

The most legally complex and politically sensitive aspect of the South China Sea dispute from Taiwan’s perspective is the establishment of maritime boundaries and Exclusive Economic Zones (EEZs). Under UNCLOS, coastal states are entitled to a 200-nautical-mile EEZ, within which they have sovereign rights over resources. However, Article 121 of UNCLOS distinguishes between rocks, which cannot generate an EEZ or continental shelf, and islands, which can.

The 2016 South China Sea Arbitration case, filed by the Philippines against the PRC, directly addressed this issue. The Permanent Court of Arbitration (PCA) ruled that many of the features occupied by China, including the Spratly Islands, were "rocks" under international law and thus could not generate an EEZ. The PRC rejected the ruling entirely. Taiwan, which was not a party to the case, also rejected the ruling, though its stated position has been nuanced. The ROC government officially maintains that its claims are "based on history, geography, and international law" and has expressed a willingness to peacefully resolve disputes. However, it has not explicitly abandoned the U-shaped line concept, creating a tension between its stated commitment to UNCLOS and the expansive nature of its traditional claims.

Taiwan’s ability to enforce its own EEZ is severely limited. Its Coast Guard patrols the waters around the Pratas and Taiping Island but faces the constant risk of confrontation with the much larger and more heavily armed maritime militias and naval forces of the PRC and other claimant states. The ROC’s diplomatic isolation means that any enforcement action it takes is rarely supported by the international community, which largely does not recognize it as a sovereign state.

Taiwan's Internal Maritime Legislation

In an effort to align its domestic law with its international posture, Taiwan has passed several pieces of legislation defining its maritime zones. The Law on the Territorial Sea and the Contiguous Zone of the Republic of China and the Law on the Exclusive Economic Zone and the Continental Shelf of the Republic of China provide the legal basis for its claims. These laws, however, are spatially expansive. They explicitly refer to the territorial seas around the islands in the South China Sea, implicitly reaffirming the traditional U-shaped line without explicitly defining its boundaries. This ambiguity allows Taipei a degree of flexibility, but it also draws criticism from other claimants who see it as an illegal extension of maritime jurisdiction.

Geopolitical Dynamics and the 'One China' Principle

The most significant constraint on Taiwan’s ability to act in the South China Sea is the "One China" principle. Since the PRC expelled the ROC from the United Nations in 1971, the vast majority of nations have recognized the PRC as the sole legitimate government of China. Consequently, Taiwan is excluded from formal multilateral mechanisms for conflict resolution in the South China Sea, such as the Association of Southeast Asian Nations (ASEAN) forums or the UNCLOS dispute resolution system.

This exclusion creates a paradoxical situation. The PRC criticizes Taiwan for wanting to participate in regional discussions, arguing that this would be a step toward recognition of "two Chinas." Yet the PRC also claims that Taiwan’s actions in the South China Sea are actions of "Chinese territory." The PRC has often stated that, in the event of a conflict over the South China Sea, it would be responsible for the defense of Taiwan’s held islands. This rhetoric, however, has not translated into a unified command structure or a cooperative defense strategy. Instead, it acts as a diplomatic tool to constrain Taipei’s independent actions.

The Role of the United States

The United States, a key security partner for Taiwan, maintains an officially neutral stance on the sovereignty disputes in the South China Sea but opposes any unilateral changes to the status quo. The U.S. considers Taiwan’s held islands to be subject to the same international legal norms as any other feature. The U.S. government has explicitly called on both the PRC and the ROC to refrain from actions that would escalate tensions. The U.S. Navy’s routine Freedom of Navigation Operations (FONOPs) in the South China Sea, which challenge the excessive maritime claims of both the PRC and the ROC, serve as a reminder that the U.S. does not differentiate between the two sides when it comes to upholding international law. This provides a complex layer of security for Taiwan, as the U.S. is bound by the Taiwan Relations Act to maintain the capacity to resist force against Taiwan, but it does not guarantee Taiwan’s territorial claims.

Strategic and Economic Stakes

The South China Sea is not just a matter of legal principle; it is a theater of hard strategic and economic interests. For Taiwan, a heavily trade-dependent island, the security of the sea lanes of communication (SLOCs) passing through the South China Sea is existential. Approximately 60% of Taiwan’s trade transits these waters, primarily through the busy Luzon Strait and the Malacca Strait. Any disruption to these routes, whether from military conflict or piracy, would cripple the Taiwanese economy.

Beyond shipping, the economic stakes include fisheries and potential hydrocarbon deposits. The waters surrounding the Pratas and Spratly Islands are rich fishing grounds, and conflicts between Taiwanese fishing vessels and the coast guards of other claimant states are common. The Guang Da Xing No. 28 incident in 2013, where a Taiwanese fishing vessel was fired upon by a Philippine Coast Guard vessel near the Bashi Channel, highlights the volatility of these encounters.

Energy security is another critical element. Geological surveys suggest significant reserves of oil and natural gas may lie beneath the South China Sea floor. While the PRC has made major investments in deep-sea drilling in the region, Taiwan has been largely unable to explore or exploit these resources due to its limited naval capacity and diplomatic isolation. This inability to capitalize on its claimed resources weakens the practical value of Taiwan's sovereignty assertions.

Conclusion: A Delicate and Continuing Source of Instability

Taiwan’s role in the South China Sea is a microcosm of the broader geopolitical challenges facing the region. It is a claimant with a tangible physical presence, a well-documented historical basis for its claims, and a strategic imperative to protect its trade routes. Yet, its ambiguous international status, stemming from the "One China" principle, leaves it in a legal and diplomatic limbo. Its claims are simultaneously reinforced by the PRC's own expansive narrative but subsumed by it, leaving no independent space for Taipe to negotiate or participate in regional order-building.

As the military and legal pressures in the South China Sea continue to intensify, the situation involving Taiwan remains a potent flashpoint. The PRC views Taiwan's participation in the dispute as an internal matter, while other claimant states and the U.S. argue for inclusive, rules-based solutions that apply equally to all parties. The future of Taiwan's held islands—Pratas and Taiping—depends on a delicate balance of power between cross-strait relations, U.S. security guarantees, and the adherence to international law. Without a broader political resolution across the Taiwan Strait, these islands will remain both a symbol of a divided nation and a potential trigger for a larger regional conflict. The status of Taiwan is not just a cross-strait issue; it is an integral component of the South China Sea dispute that cannot be resolved in isolation.