China Rejects Philippine Maritime Chart as South China Sea Dispute Turns to Maps

Beijing calls the chart illegal

Guo said the Philippines’ “designation” of the Kalayaan Island Group and its updated chart were “illegal, null and void.” He argued that the islands and reefs covered by the document lie outside Philippine territory as defined by historical treaties.¹ He said China “firmly opposes” Philippine actions that harm China’s sovereignty, rights and interests, and would continue to defend its claims in the South China Sea.¹

Bastille Post reported that the Chinese response followed reports that Manila’s updated chart included Zhongye Dao, Mahuan Dao and other islands and reefs within what Beijing calls Nansha Qundao.² Chinese state-linked media echoed that framing, presenting the Philippine chart as an infringement on Chinese sovereignty rather than as an administrative or navigational document.³

That distinction matters for maritime security watchers. For Manila, charts and coordinates are part of an effort to align national documentation with the United Nations Convention on the Law of the Sea, or UNCLOS, and to publicize the legal basis of Philippine jurisdiction. For Beijing, the same documents are viewed through a sovereignty-first narrative that rejects Philippine control over features it says belong to China.¹⁶

Mapping joins patrols as a pressure point

The cartographic dispute unfolded alongside fresh activity at sea. On September 29, the Philippine Coast Guard said it had driven away a Chinese maritime militia vessel and 24 small boats near Kota Island, another feature in the Kalayaan Island Group, after they were monitored about 1.2 nautical miles northwest of the island on September 28.⁵

The PCG said the Chinese vessel launched two dozen small boats, or sampans, which spread out near the island before leaving after a Philippine Coast Guard team challenged them.⁵ Philippine officials described the operation as unauthorized fishing in Kota Island’s territorial sea and cited Philippine sovereignty, fisheries law and UNCLOS.⁵

Philstar reported that Kota Island is part of Kalayaan town in Palawan and that the Kalayaan Island Group remains central to South China Sea disputes, with China claiming sovereignty over nearly the entire area.⁶ The report also noted that China has rejected the 2016 arbitral ruling under UNCLOS, which found no legal basis for Beijing’s expansive maritime claims.⁶

PTV News separately reported Philippine Coast Guard concern over Chinese maritime activity near Batanes and noted the Kota Island incident. The report placed the Kalayaan encounter within a broader pattern of Philippine efforts to monitor, document and publicly disclose Chinese vessel movements.⁷

Competing records of control

The September 29 exchange shows how both sides are building records for different audiences. Manila’s charts, patrol reports and UNCLOS references are aimed at establishing an official paper trail of jurisdiction and law-enforcement activity. Beijing’s response seeks to deny the legitimacy of that record by asserting prior sovereignty over the same features and rejecting Philippine terminology such as “Kalayaan Island Group.”¹³

The result is a dispute increasingly fought in parallel arenas: on the water, where coast guard and militia vessels test presence and access; and in official documentation, where maps, place names and maritime zones reinforce national claims.⁵⁶

For now, neither side’s language suggests a retreat. Manila continues to present its actions as law-based administration of Philippine waters and territories, while Beijing says Philippine mapping and occupation of features in the Spratlys violate Chinese sovereignty.¹⁵ The updated chart has therefore become more than a technical document. It is a new front in the struggle over who defines the legal and geographic reality of the South China Sea.