The South China Sea remains one of the most contested regions in the world, with various countries vying for control over its islands, reefs, and shoals. Among these contested features, the Second Thomas Shoal—a submerged reef within the Spratly Islands—has emerged as a key flashpoint. Known locally in the Philippines as Ayungin Shoal, it holds strategic, geopolitical, and symbolic value. For the Philippines, it represents sovereignty and serves as an essential national defense outpost. For China, however, it is part of the expansive territory it claims under the controversial Nine-Dash Line. The growing tensions surrounding Second Thomas Shoal underscore the complexities of the South China Sea dispute.
This article examines the geographical significance, history, and legal dynamics of the shoal, along with the current diplomatic challenges it presents for the Philippines, China, and the broader region.
Location and Strategic Importance of Second Thomas Shoal
Second Thomas Shoal lies approximately 105 nautical miles west of Palawan, a province of the Philippines. It is part of the Spratly Islands, an archipelago made up of reefs, atolls, and islets scattered across the South China Sea. While the shoal is submerged during high tide, it gains significance as part of the Philippines’ Exclusive Economic Zone (EEZ), as defined by the United Nations Convention on the Law of the Sea (UNCLOS).
The South China Sea is crucial not only for its marine resources but also for its strategic location along important maritime trade routes. Countries in the region rely on these sea lanes for commercial shipping, and any disruption in the area could have global economic ramifications. Second Thomas Shoal is positioned near rich fishing grounds and potential oil and gas reserves, making it an area of strategic and economic importance.
For the Philippines, maintaining a foothold on the shoal reinforces its claim over the Spratly Islands. However, China considers the Second Thomas Shoal to be part of its territory, claiming it as within its Nine-Dash Line, which encompasses nearly the entire South China Sea.
Historical Background and the BRP Sierra Madre
The Philippine Navy took a bold step in 1999 by intentionally grounding the BRP Sierra Madre on the Second Thomas Shoal. The Sierra Madre is a rusting World War II-era landing ship that has remained aground for more than two decades, now serving as an outpost for a handful of Filipino marines.
This act was a strategic move by the Philippines to maintain a physical presence on the shoal and prevent other nations from occupying it. Over the years, the BRP Sierra Madre has become a symbol of Philippine sovereignty in the South China Sea. The deteriorating ship, still manned by a small military crew, plays a pivotal role in asserting the Philippines’ territorial claim.
China, however, has consistently demanded the removal of the ship, accusing the Philippines of violating its sovereignty. Despite China’s opposition, the Philippines has refused to abandon the outpost, viewing it as a vital part of its national defense strategy.
Legal Framework and the 2016 Arbitral Tribunal Ruling
The South China Sea dispute, including the conflict over Second Thomas Shoal, is governed by UNCLOS. This international treaty defines the rights and responsibilities of coastal states regarding their territorial waters and exclusive economic zones. Since Second Thomas Shoal lies well within the Philippines’ EEZ, Manila argues that it has legitimate rights over the area.
In 2013, the Philippines filed a case at the Permanent Court of Arbitration in The Hague, challenging China’s claims under the Nine-Dash Line. In 2016, the tribunal ruled in favor of the Philippines, stating that China’s expansive maritime claims had no legal basis. The ruling also recognized that the Philippines has sovereign rights over the waters within its EEZ, including those around Second Thomas Shoal.
However, China has rejected the ruling and continued its activities in the South China Sea, asserting that the tribunal has no jurisdiction over the matter. The Philippines has repeatedly called on the international community to support the enforcement of the ruling, but the lack of binding enforcement mechanisms has limited its impact.
Current Diplomatic and Military Tensions
Tensions over the Second Thomas Shoal have intensified in recent years, with both the Philippines and China taking actions that reflect the broader struggle for control over the South China Sea. The presence of the BRP Sierra Madre and Filipino marines on the shoal remains a key point of friction. China frequently sends coast guard vessels and maritime militia ships to patrol the area, increasing the risk of confrontation.
In response to what it sees as Chinese aggression, the Philippine government has bolstered its diplomatic efforts by strengthening alliances with countries like the United States and Japan. Recent joint military exercises in the region have signaled the Philippines’ resolve to defend its maritime claims, including those at Second Thomas Shoal.
In August 2023, a standoff occurred when Chinese Coast Guard ships blocked a Philippine resupply mission to the BRP Sierra Madre, leading to diplomatic protests from the Philippines. These incidents highlight the delicate balance between diplomacy and military posturing in the South China Sea, with the Second Thomas Shoal serving as a microcosm of the larger regional conflict.
Broader Geopolitical Implications
The conflict over Second Thomas Shoal reflects the broader geopolitical struggle in the Indo-Pacific region. The South China Sea is a critical theater for competing powers, including the United States and China, whose strategic interests clash over freedom of navigation and territorial sovereignty.
China’s growing influence and assertiveness in the South China Sea have prompted the United States to reaffirm its commitment to defending its allies in the region, particularly the Philippines. The Mutual Defense Treaty between the Philippines and the United States obligates both countries to come to each other’s aid in case of an armed attack, further complicating the situation. This dynamic has raised concerns about the potential for escalation in the region.
At the same time, other Southeast Asian countries with competing claims—such as Vietnam, Malaysia, and Brunei—are closely watching developments at Second Thomas Shoal. How the Philippines and China handle their differences could set a precedent for resolving other disputes in the South China Sea.
Conclusion
Second Thomas Shoal stands at the heart of the South China Sea dispute, symbolizing the complex interplay of sovereignty, national defense, and regional geopolitics. For the Philippines, maintaining its foothold on the shoal through the presence of the BRP Sierra Madre is a critical part of its strategy to assert control over its maritime territories. For China, however, the shoal represents yet another battleground in its broader push to consolidate power over the South China Sea.
Despite the 2016 arbitral tribunal ruling in favor of the Philippines, tensions continue to simmer as diplomatic efforts to resolve the dispute remain fragile. The standoff at Second Thomas Shoal underscores the delicate balance between power and diplomacy in one of the world’s most contested maritime regions.
The outcome of this dispute could have significant implications not only for the Philippines and China but for the entire Indo-Pacific region, where control over the South China Sea will shape the future of trade, security, and regional stability.
