The Philippines in many ways is the frontline of the South China Sea dispute. It presides over a ‘hot’ and ongoing conflict against the PLA Navy and China’s irregular maritime forces, with features like the Scarborough Shoal, Second Thomas Shoal, and more recently the Sabina Shoal sites of frequent ‘gray zone’ clashes. The Philippines’ EEZ is home to some of China’s most ambitious claims given their geographic distance from the Chinese mainland. And this is the only instance of international law weighing in on the legality of South China Sea claims owing to a case brought against China at the Permanent Court of Arbitration in 2013. And finally, the fact that Manila is a treaty ally with the military backing of the US Navy adds significant weight to the conflict, increasing the geopolitical risk of any miscalculation or escalation.

Philippines Legal Claims in the South China Sea

The Philippines lays claim to two sets of disputed features in the South China Sea: the Scarborough Shoal off the western coast of Luzon, and a group of 50 features in the Spratly Islands called the Kalayaan island group (KIG), located off the western coast of Palawan. The KIG includes prominent Philippines-occupied features such as Commodore Reef (occupied in 1978), Nanshan Island (1974), Flat Island (1974), West York Island (1974), Loaita Island (1978), Thitu Island (1974), and Northeast Cay (1968).

The claim to the Scarborough Shoal rests on several planks:

  1. Records that the US Navy visited, mapped, and exercised jurisdiction over the area during the colonial era (the legal rights of which passed completely to Manila upon independence).
  2. The Scarborough Shoal being geographically much closer to the Philippines than it is China, lying just 120 nautical miles from Luzon and thus falling within the country’s EEZ under the United Nations Convention on the Law of the Sea (UNCLOS).
  3. The shoal appearing on various Spanish maps in the 16th and 17th
  4. Instances of the Philippines government exercising jurisdiction in the 20th century (e.g., in 1963 the Philippine Navy expelled smugglers from Macro who were operating in the area).

The claim to the Kalayaan island group zone is weaker according to a legal assessment conducted for US Congress in 2014 by the CNA group. According to CNA, the Philippines’ claim here is similar to China’s nine-dash line in that it lacks a firm basis in modern international law and came later than other claimants like Vietnam, China, and the Republic of China (Taiwan). Yet despite this, the Philippines can make a strong legal case for four high-tide elevations in the KIG based simply on the fact that it was the first country to discover them and they were not specifically cited in other claims, particularly those being advanced by Vietnam. These features are: West Work Island, Nanshan Island, Flat Island, and Lankiam Cay.

The Philippines began its permanent occupation of features in the Spratly Islands in the late 1960s and 1970s. The decision came on the heels of several regional developments: 1) skirmishes between Palawan-based fishermen and Republic of China boats operating out of Itu Aba Island (Taiping Island); 2) the discovery of oil and gas reserves in the area; 3) China’s seizure of Vietnam-occupied features in the Paracels in 1974-75; and 4) Vietnam’s subsequent decision to start permanently occupying features in the Spratly Islands.

In terms of ground-level presence, Manila lags behind China and Vietnam in both facilities and land-reclamation on occupied features. Thitu Island – the second-largest feature in the Spratlys – is the country’s primary outpost and its sole airstrip. Other features such as Commodore Reef, Flat Island, Loaita Island, Nanshan Island, and Northeast Cay have barracks and supporting facilities for a small troop presence. In 2017, President Duterte followed through with an initiative from his predecessor to upgrade the airstrip at Thitu Island, along with the barracks and water systems of nine other Philippine-occupied features in the South China Sea.

China-Philippines Standoff at the Scarborough Shoal

The Scarborough Shoal is the largest shoal in the South China Sea. At present, it remains undeveloped and is mostly submerged at high tide. However, there have been indications that a land reclamation project is in China’s long-term plans, which would be a necessary step toward establishing new permanent military infrastructure.