By Prof. Anna Malindog-Uy

 

By Anna Malindog-Uy

The Philippines’ extended continental shelf claim in the West Palawan Region is becoming one of the more consequential, yet often misunderstood, legal contests in the disputed South China Sea (SCS).

What makes it especially interesting is that the objections from China, Malaysia, Vietnam and Taiwan are not based on the same legal argument.

They overlap geographically, but each claimant is defending a different bundle of sovereignty, maritime rights and entitlements, and strategic interests.

The latest development occurred in late July 2026, when the Philippines formally presented its case before the UN Commission on the Limits of the Continental Shelf (CLCS).

The underlying submission, however, was filed on June 14, 2024. It concerns the seabed beyond the Philippines’ ordinary 200-nautical-mile continental shelf in the West Palawan Region. 

The first misconception to clear away is important: The Philippines is not asking the UN to award it another 150 nautical miles of territorial sea or an exclusive economic zone (EEZ).

Under Article 76 of UNCLOS (United Nations Convention on the Law of the Sea), a coastal state may establish a continental shelf beyond 200 nautical miles where the natural continental margin satisfies prescribed geological and geomorphological criteria, which simply means scientific evidence showing that the seabed beyond 200 nautical miles is a natural continuation of a country’s continental landmass, subject generally to an outer constraint of 350 nautical miles.

The rights at issue are primarily sovereign rights over the seabed and subsoil, and their natural resources. They do not convert the waters above that extended shelf into Philippine territorial waters.

That distinction is central to understanding both Manila’s claim and the objections coming from other SCS claimant states. 

The Philippines Claim

The Philippines essentially argues that the continental margin extending westward from Palawan extends beyond 200 nautical miles, thereby giving it an entitlement under Article 76 of UNCLOS to an ECS. The UN docket records formal communications concerning it from China, Malaysia, and Vietnam.  

In its 2026 presentation, Manila asked the CLCS to take account of decisions of tribunals constituted under UNCLOS, including the 2016 SCS Arbitral Award. This is strategically controversial, especially for other SCS claimants, because the award concluded, among other things, that none of the Spratly features is capable of generating a 200-nautical-mile EEZ or continental shelf of its own. This makes the geological filing burdened with geopolitical consequences. 

What makes the Philippine extended continental shelf submission even more intriguing is the chorus of objections from other SCS claimants, Malaysia, Vietnam, China, and even Taiwan. But it would be analytically misleading to reduce this emerging controversy to a simplistic narrative of “four SCS claimants versus the Philippines.” They may all object to Manila’s submission, but for different reasons, invoking distinct legal principles, geopolitical arguments, and defending different strategic interests.

Malaysia’s objections

Malaysia’s objection is considerably more sensitive than an ordinary disagreement over overlapping continental shelves because it intersects with the unresolved historical question of Sabah. Kuala Lumpur (KL) contends that Manila’s West Palawan extended continental shelf submission relies, at least in part, on geographical premises or projections associated with Sabah and overlaps seabed that Malaysia regards as belonging to its continental shelf.

The Philippines, for its part, has disputed Malaysia’s characterization of the submission and maintains that its continental-shelf claim is based on its own lawful baselines and the geological prolongation of the Philippine landmass under Article 76 of UNCLOS. Nevertheless, Malaysia views the submission not merely as an SCS maritime dispute but as touching on the longstanding Philippine claim to North Borneo/Sabah.

Malaysia’s objection to the Philippine seabed submission must therefore be understood on two levels. The first is a UNCLOS question: whether portions of the Philippine extended continental shelf overlap with maritime areas to which Malaysia itself claims continental shelf entitlement.

The second is potentially more fundamental: what land territory may legally generate those maritime entitlements in the first place. Under the basic principle that “the land dominates the sea,” maritime rights ultimately derive from sovereignty over land territory. If Malaysia believes that the Philippine submission depends on baselines, coastal geography, or projections that implicitly presuppose Philippine rights connected with Sabah, Kuala Lumpur will naturally regard the matter as touching not merely on seabed delimitation but on territorial sovereignty itself.

Malaysia’s 2024 diplomatic note and its July 24, 2026, formal protest to the UN stated that it categorically rejected the Philippine submission because it considered the Philippine continental margin to have been projected from Sabah’s baselines, and KL maintains that Sabah is indisputably Malaysian territory and rejects Philippine claims to it.

Indeed, the Malaysian contention is qualitatively different because it is not purely geological or hydrographic but is more politically and legally complicated, apparently showing that technical law-of-the-a exercise can reopen much older questions of territory and sovereignty.  Therefore, Manila and Kuala Lumpur must manage this particular objection prudently and carefully so that it does not escalate into a heightened territorial dispute between the two ASEAN neighbors.

China’s contention

China and Vietnam may be objecting to the same Philippine submission, but they are not making the same case, not even close.

This distinction is crucial. China and Vietnam are not standing on the same legal ground; they simply arrive at the same contested seabed from very different directions.

And understanding that difference is essential to understanding not only the Philippine claim, but the deeper contradictions, competing legal narratives, and strategic realities that continue to define the disputed waters of the SCS. 

China’s broadest and most fundamental objection to Manila’s latest presentation at the CLCS (Commission on the Limits of the Continental Shelf) is the contention that the Philippine submission infringes China’s sovereignty, sovereign rights, and jurisdiction.

Beijing argues it has sovereignty over the Nansha Qundao—the Spratly Islands—and other SCS island groups, along with the maritime rights and interests that derive from them. 

China’s objection therefore operates on several levels. First is territorial sovereignty. Beijing says the Spratly Islands belong to China. Since parts of the Philippine ECS submission extend through areas associated with the Spratly dispute, China contends that Manila cannot unilaterally establish seabed rights since the sovereignty dispute in the SCS remains contested.

Second is maritime entitlement. China continues to claim maritime rights derived from the Nansha and other SCS island groups.

Third and most controversial, China rejects the 2016 Arbitral Award. Beijing regards that ruling as invalid and without legal effect, whereas the Philippines regards it as final and binding between the Philippines and China.

The award rejected the legal basis for China’s historic-rights claims insofar as they exceeded the maritime entitlements permitted by UNCLOS (United Nations Convention on the Law of the Sea). 

Why does the 2016 arbitral award matter enormously and crucially? 

Suppose, for argument’s sake, that a Spratly feature could generate a 200-nautical-mile EEZ (exclusive economic zone) and continental shelf; its entitlement could overlap dramatically with an extended shelf projected westward from Palawan.

But if, as the 2016 arbitral tribunal ruled, none of the Spratly features generates an EEZ or continental shelf, the legal picture changes radically. The potential maritime zones generated by those features shrink essentially to territorial seas around qualifying high-tide features.

That leaves considerably more space for continental-shelf claims generated from the large mainland or archipelagic coasts of states such as the Philippines, Vietnam and Malaysia.

So, Manila’s ECS submission is not merely citing the arbitral award ceremonially. It is attempting to translate the 2016 arbitral award from an abstract “legal victory” into an actual map of maritime entitlements. This is perhaps precisely why Beijing objects so strongly.

Vietnam’s position

Vietnam perhaps has the most conventional maritime-overlap dispute with the Philippines over the contested waters of the South China Sea (SCS). Its objection to the Philippines’ UN seabed submission is far more conventional under the law of the sea.

It argues that portions of Manila’s claimed extended continental shelf overlap with maritime entitlements that Vietnam itself asserts under UNCLOS (United Nations Convention on the Law of the Sea), and Spratly sovereignty, challenging the very legal architecture Manila relies on.

After the Philippines filed its claim, Hanoi formally rejected the portion of Manila’s claimed extended shelf that it said encroached on Vietnam’s continental shelf and overlapped Vietnam’s own Extended Continental Shelf (ECS) entitlement. Nevertheless, Vietnam signaled willingness to negotiate with the Philippines.

On July 17, 2024, Vietnam filed its own extended continental shelf submission concerning the Central Area of the SCS. The UN records this immediately after the Philippine submission, Philippines submission No. 94, and Vietnam submission No. 95.

Vietnam also reaffirmed its sovereignty claims over the Paracel and Spratly Islands. But there is an important distinction. Hanoi and Manila are largely arguing within the same UNCLOS framework.

Vietnam is not necessarily saying: “UNCLOS does not apply because we possess historic rights over virtually this entire sea.” It is essentially saying: “UNCLOS applies, but if you calculate continental-shelf entitlements correctly, part of the seabed you claim is also ours.”

That is a much more conventional maritime delimitation dispute.

Two states can both possess legitimate continental-shelf entitlements that overlap. Neither claim automatically extinguishes the other. The ultimate boundary would normally have to be negotiated, agreed upon or adjudicated separately.

And crucially, the Commission on the Limits of the Continental Shelf (CLCS) cannot draw that boundary for Manila and Hanoi. Its function is to assess the scientific and technical basis for the outer edge of a continental margin, not determine which claimant gets an overlapping slice of seabed. UNCLOS specifically preserves maritime delimitation questions from CLCS determinations.

Note that a CLCS recommendation would not settle sovereignty disputes/issues.

It lacks competence to settle or decide sovereignty over the Spratly Islands, award Sabah, delimit the Philippines-Vietnam boundary, or resolve China-Philippines maritime disputes.

The CLCS is not an international court. Its expertise is geology, hydrography, and continental-margin delineation.

This helps explain in many ways why Philippine-Vietnamese rhetoric has generally been far less confrontational than Philippine-Chinese rhetoric. Manila has publicly said it is prepared to work with Vietnam toward a mutually acceptable solution under international law.

This difference matters. Vietnam’s opposition is potentially negotiable, while China’s objection reflects a deeper disagreement over the legal architecture governing the SCS. 

Best foot  forward?

Now, among the SCS claimants, which objections are strongest? That depends on whether we mean procedural or substantive objections. Procedurally, the objections are very consequential.

The biggest obstacle for the Philippines is not necessarily persuading geologists. It is the CLCS (Commission on the Limits of the Continental Shelf)rule on disputed areas.

The Commission’s Rules of Procedure say that where a land or maritime dispute exists, it shall not examine and qualify a submission by a state concerned in the dispute without the necessary consent of the states involved. That means a Philippine submission can be scientifically impressive and legally sophisticated and still sit unresolved for years because of overlapping disputes. 

Substantively, however, the objections differ considerably. Vietnam’s argument is probably the most orthodox UNCLOS dispute: two coastal states assert overlapping continental shelves. That eventually calls for delimitation.

Malaysia’s objection is potentially formidable because it introduces Sabah. If determining the relevant continental margin requires resolving disputed territorial premises, the CLCS simply lacks jurisdiction to settle the underlying sovereignty question.

China’s objection is politically the most powerful but legally the most contested, because much of the disagreement stems from Beijing’s rejection of the 2016 Arbitral Award’s interpretation of SCS maritime entitlements. 

So why is the Philippines’ filing more than a technical seabed exercise, and what is the bigger strategic significance?

First, Manila is trying to operationalize the 2016 arbitral award. Second, Manila is pushing the dispute from ships and water cannons toward law, maps, and geology. Instead of arguing exclusively about who controls a reef today, Manila is asking a longer-term question: Whose continental landmass naturally continues beneath the seabed? That is a much more durable form of claim-building.

However, Manila has simultaneously created complications with two ASEAN partners. This is the strategic downside. Thus, the Philippines has to avoid turning a potentially useful ASEAN convergence on maritime law into three competing nationalist contests over seabed territory. 

Conclusion

The Philippine seabed submission has exposed something important about the SCS dispute: There is not one dispute—there are several disputes layered on top of one another.

The good thing is that Manila has put its scientific and legal position formally on record. It has also shifted part of the contest away from coast-guard confrontations and toward a more demanding question: If every claimant says its rights are lawful, exactly which provisions of international law generate those rights, from which land territory, and how far can they legitimately extend?

For the Philippines, this is both the strategy’s strength and its risk. UNCLOS provides a powerful framework for challenging excessive claims, but the same law also requires Manila to negotiate genuine overlaps with Malaysia and Vietnam rather than treating every competing claim as equivalent to China’s.

This distinction will be crucial if the Philippines wants to defend its maritime entitlements without unnecessarily alienating ASEAN neighbors whose legal interests partly converge with its own.

   

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