By Liz Lagniton | 2026-04-13

Former Philippine Supreme Court associate justice Antonio Carpio contended that international naval exercises in the West Philippine Sea (WPS) highlight growing recognition of the Philippines' maritime claims. Those claims are based on a 2016 arbitral court's rejection of China's case that more than 80% of the South China Sea is its maritime territory.

The WPS is Manila's name for the part of the South China Sea inside its Exclusive Economic Zone.

Speaking in an April 1 television interview as reported by Philippine Star, Carpio cited joint naval operations in disputed waters by the United States and its allies. Other participants this year have included Japan and Australia.

Those naval drills are anchored on the 2016 ruling at The Hague, said Carpio.

That court rejected Beijing's "nine-dash-line" claim over most of the South China Sea. In 2023, China put out a revised 10-dash line, thereby demanding even more territory.

"The US conduct naval drills, they [other allies] conduct naval drills and they point to the arbitral award," said Carpio.

Legal signals

Such activities signal de facto recognition of the decision by major powers, even as China continues to call large parts of the contested waters its territory, said Carpio.

Freedom-of-navigation operations and multilateral exercises in the WPS demonstrate that other countries dismiss Beijing's contentions, said Carpio.

However, such actions fall short of full enforcement of the ruling, he said, citing Manila's lag in resource extraction at sea.

Hesitation in Manila

By not seeking energy in its own waters, the Philippines has yet to fully benefit from the court's decision, said Carpio.

"That (2016 ruling) is not a complete enforcement, because we cannot get the [natural] gas in Reed Bank," he said.

He contrasted Manila's reluctance to rile China with the attitude of Malaysia and Indonesia.

These countries have continued drilling for oil and gas with backing from the United States and Australia. It allows them to operate in contested waters with greater confidence, he said.

Manila has failed to line up similar help, he said. "They've (US, Australia) offered that, but we have refused."

Beyond resource development, Carpio has urged the government to consider more arbitration against China, particularly over restrictions on Filipino fishing in Scarborough Shoal.

"We should be able to fish there, but the Chinese have prevented us and the Vietnamese from fishing ... So it's a clear case," he said.

But enforcement ultimately depends on political will and sustained state action, said Carpio.

The WPS remains a flashpoint amid ongoing maritime tensions and increased military activity in the region.

The Philippines has stepped up joint exercises with allies, including the United States and Australia, most recently through multilateral maritime cooperative activities held in February.

Naming places

Meanwhile, the government has taken steps to reinforce its claims administratively.

On March 26, President Ferdinand Marcos Jr. signed an executive order assigning official Philippine names to features in the Kalayaan Island Group in Palawan province. Situated within the Spratly archipelago, the area has been a site of repeated confrontations between Philippine and Chinese vessels.

The directive requires government agencies to adopt these names in all official maps, documents and communications. The South China Sea contains approximately 250 islands, atolls and shoals.

China's Foreign Ministry stated on April 1 that it "firmly opposes" the move and said it would take "necessary" measures to safeguard its territorial sovereignty and maritime rights.

The Spratly Islands are believed to hold significant oil and natural gas reserves. Multiple claimants, including the Philippines, China, Brunei, Malaysia, Taiwan and Vietnam, say they own the archipelago.