Whitsun Reef

Whitsun Reef (Philippine name: Julian Felipe Reef; Chinese name: Niu'e Jiao 牛轭礁) is a boomerang-shaped reef in the Union Banks of the Spratly Islands, lying roughly 175 nautical miles west of Bataraza, Palawan — well inside the 200-nautical-mile Exclusive Economic Zone the Philippines claims under the UN Convention on the Law of the Sea (UNCLOS). The reef is also claimed by China and Vietnam as part of the broader Spratlys dispute.

The feature drew international attention in March 2021, when the Philippine Coast Guard and the National Task Force for the West Philippine Sea reported that some 220 Chinese vessels — described by Manila as militia boats and by Beijing as fishing vessels sheltering from rough seas — were moored in a line at the reef. The Department of Foreign Affairs filed a diplomatic protest on 21 March 2021, and then-Defense Secretary Delfin Lorenzana publicly demanded the ships' withdrawal. The United States, Japan, Australia, and the EU issued statements of concern, framing the gathering as part of China's use of maritime militia (sometimes called the "little blue men") to assert presence without overt naval deployment.

The episode is frequently cited as evidence of "gray-zone" tactics — coercive activity below the threshold of armed conflict — and as a follow-on test of the 2016 South China Sea Arbitration award (PCA Case No. 2013-19), which found that China's nine-dash line claim had no legal basis under UNCLOS and that several Spratly features, including those in the Union Banks, generate no entitlement beyond a 12-nautical-mile territorial sea (if any). Whitsun Reef itself was characterized in that ruling's reasoning as a low-tide elevation, meaning under UNCLOS it cannot be appropriated as sovereign territory on its own and falls within the seabed regime of the nearest coastal state's continental shelf — strengthening Manila's legal position even as Chinese vessels have continued intermittent presence at the site through 2022–2024.