Regime of Islands | Inquirer Opinion

Regime of Islands

The Kalayaan Island Group (KIG) was formally incorporated into Philippine territory under Presidential Decree No. 1596 dated June 11, 1978. PD 1596 states, “The area within (a description of the coordinates of the KIG polygonal lines) xxx shall belong and be subject to the sovereignty of the Philippines.” This means that the Philippines claimed everything within the polygonal lines as Philippine territory, even waters and resources beyond the territorial seas of high-tide geologic features within the polygonal lines.

Under international law in 1978, states could claim only a three nautical mile territorial sea from the low water mark of a high-tide feature. Under the 1982 UN Convention on the Law of the Sea or Unclos, this territorial sea was extended to 12 nautical miles. However, PD 1596 still violated Unclos insofar as it claimed as Philippine territory waters and resources beyond 12 nautical miles from high-tide features within the KIG polygonal lines.


When the Philippines ratified Unclos on May 8, 1984, the Philippines undertook to align in good faith its domestic law with Unclos. Thus, Congress passed Republic Act No. 9522 on March 10, 2009 to comply with our obligation under Unclos. Section 2 of RA 9522 provides: “The baseline in the following areas over which the Philippines likewise exercises sovereignty and jurisdiction shall be determined as ‘Regime of Islands’ under the Republic of the Philippines consistent with Article 121 of the United Nations Convention on the Law of the Sea (Unclos): (a) The Kalayaan Island Group as constituted under Presidential Decree No. 1596; and (b) Bajo de Masinloc, also known as Scarborough Shoal.”

Under RA 9522, the baseline of an island, from which the territorial sea is measured, shall be determined in accordance with the Regime of Islands under Article 121 of Unclos. Article 121 provides that an island must be above water at high tide. Hence, a geologic feature below water at high tide is not an island and is not entitled to a territorial sea. Under RA 9522, the Philippines now claims as Philippine territory only geologic features above water at high tide, together with their territorial seas. In compliance with Unclos, the Philippines under RA 9522 no longer claims as Philippine territory low-tide geologic features, waters, and resources beyond the territorial sea.


Section 2 of RA 9522 refers to the determination of the baseline of islands in the “[t]he Kalayaan Island Group as constituted under Presidential Decree No. 1596.” The islands referred to are the high-tide geologic features found within the same polygonal lines of PD 1596 as they are the islands “constituted under Presidential Decree No. 1596.” Under RA 9522, the interpretation of the polygonal lines has changed, from a claim to all the geologic features, waters, and resources found within the polygonal lines, to a claim to only all the high-tide features and their territorial seas found within the polygonal lines. Clearly, the polygonal lines under PD 1596 have not been abrogated but merely reinterpreted to comply with Unclos.

When the Philippines filed its arbitration case against China on Jan. 22, 2013, the Philippines had already enacted RA 9522 which fully aligned Philippine domestic law with Unclos. During the proceedings, the lawyers of the Philippines submitted a copy of RA 9522, together with a copy of the 2011 Supreme Court decision in Magallona v. Ermita which affirmed the constitutionality of RA 9522, to establish that the Philippines had fulfilled in good faith its obligation to align its domestic law with Unclos.

During the arbitration, the Philippine lawyers were aware that China had illegally drawn straight baselines around the Paracels. The Philippine lawyers were worried that China would also declare straight baselines around the Spratlys. Thus, the Philippine lawyers on their own raised the issue that straight baselines could not be drawn around the Spratlys. In response, the arbitral tribunal stated in its final Award of July 12, 2016: “In the Tribunal’s view, any application of straight baselines to the Spratly Islands in this fashion would be contrary to the Convention. Article 7 provides for the application of straight baselines only “[i]n localities where the coastline is deeply indented and cut into, or if there is a fringe of islands along the coast in its immediate vicinity.”

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TAGS: Antonio T. Carpio, Crosscurrents, Kalayaan Island Group, Maritime Dispute, regime of islands, West Philippine Sea
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