Second Thomas Shoal

Second Thomas Shoal, also known as Ayungin Shoal (Buhanginan ng Ayungin), Bãi Cỏ Mây (Vietnamese) and Rén'ài Jiāo, is a submerged reef in the Spratly Islands of the South China Sea, 105 nmi west of Palawan, Philippines. It is a disputed territory and claimed by multiple nations.

The reef is occupied by Philippine Navy personnel aboard a ship, the BRP Sierra Madre, that was intentionally grounded on the reef in 1999 and has been periodically replenished since then.

History
The atoll is one of three named after Thomas Gilbert, captain of the Charlotte:


 * First Thomas Shoal –, South of Second Thomas Shoal.
 * Second Thomas Shoal –, Southeast of Mischief Reef.
 * Third Thomas Shoal –, Northeast of Flat Island – some distance North of Second Thomas Shoal.

Geographical location
Located south-east of Mischief Reef, Second Thomas Shoal is near the centre of Dangerous Ground in the north-eastern part of the Spratly Islands. There are no settlements north or east of it. It is a tear-drop shaped atoll, 11 nmi long, from north to south and fringed with coral reefs. The coral rim surrounds a lagoon, which has depths of up to 27 m and is accessible to small boats from the east. Drying reef patches are found east and west of the reef rim.

Geographical features
On 12 July 2016, the UNCLOS tribunal at the Permanent Court of Arbitration concluded that Second Thomas Shoal is, or in its natural condition was, exposed at low tide and submerged at high tide and, accordingly, has low-tide elevations that do not generate an entitlement to a territorial sea, exclusive economic zone or continental shelf.

Territorial claims
Second Thomas Shoal is claimed by China, the Philippines, Taiwan and Vietnam.

The Philippine Navy maintains a presence of less than a dozen Marine personnel on a 100 m long Second World War US-built Philippine Navy landing craft, the Sierra Madre, which was deliberately run aground at the atoll in 1999, in response to the Chinese reclamation of Mischief Reef. The Philippines claims that the atoll is part of its continental shelf. Parts of the Spratly group of islands, where Second Thomas Shoal lies, are claimed by China, Brunei, the Philippines, Malaysia and Vietnam.

Philippine supply ships avoided Chinese blockades in order to deliver food, water and other supplies to the garrison. PRC coast guard vessels blocked two attempts by Philippine ships to resupply the garrison on March 9, 2014. Supplies were airdropped to the garrison three days later. A supply ship with replacement troops successfully reached the atoll on March 29, 2014, by sailing through shallow waters where the PRC vessels, having deeper drafts, were unable to follow. Since then, the Philippine military has been sending relief and provisions by supply boats.

In 1999, president Joseph Estrada promised that the vessel would be towed away. In 2014, the Chinese government asked the Philippines to remove the grounded ship. The Philippine president Bongbong Marcos said in 2023, “I am not aware of such agreement. If there was, I rescind it as of this moment.”

In 2017, China and the Philippines established a gentlemen's agreement that the status quo be maintained for the South China Sea, as both sides tried to strengthen their relations. Under the status quo agreement, no construction materials are allowed to fortify the Sierra Madre.

In November 2021, China Coast Guard (CCG) vessels used water cannons and blocked two Philippine supply boats, preventing the boats from delivering essential supplies to the Philippine marines stationed on the Sierra Madre. It happened again in August 2023, when Chinese Coast Guard ships fired water cannons at a Philippine Coast Guard ship resupplying the Sierra Madre. The Navy-operated boat carried food, water and repair material for Sierra Madre. On 22 October 2023, Philippine officials disclosed that Chinese vessels had rammed a Philippine Coast Guard ship and military-run supply boat on 17 October, during a replenishment mission to the Sierra Madre.

In April 2024, President Marcos said he was ‘horrified’ by revelations of Xi Jinping and Duterte's secret ‘gentlemen’s agreement’ for preserving the status quo in disputed waters. Later that April, China claimed to have reached an agreement with the Philippines in adopting a "new model" over the disputed atoll. The claim was refuted by the Philippines, with defense secretary Gilberto Teodoro stating that the Philippines would not enter into any agreements compromising its territorial claims.

Alternate names
The Singapore National University Gazetteer, and the US NGA Gazetteer list the following as other names for the Second Thomas Shoal:
 * Filipino – Ayungin
 * French – Banc Thomas Deuxième
 * Mandarin Chinese – Ren'ai Jiao
 * Other Chinese names – Jen-ai An-sha, Jen-ai Chiao, Jên-ai Chiao, Ren'ai Ansha, 仁愛暗沙, 仁爱礁, 断节
 * Other English names – Thomas Shoal Second
 * Other names – Duanjie
 * Vietnamese – Bãi Cỏ Mây