Second Thomas Shoal, also known as Ayungin Shoal (; ; and Mandarin ), is a shoal or atoll in the Spratly Islands of the South China Sea, west of Palawan, Philippines. Claimed by several nations, the shoal is currently militarily occupied by the Philippines. History The shoal is one of three named after Thomas Gilbert, captain of the : First Thomas Shoal – (South of Second Thomas Shoal) Second Thomas Shoal – (Southeast of Mischief Reef) Third Thomas Shoal – (Northeast of Flat Island - some distance N 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, long north–south and fringed with coral reefs. The coral rim surrounds a lagoon which has depths of up to and is accessible to small boats from the East. Drying patches are found east and west of the reef rim. Geographical features On 12 July 2016, the tribunal of 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 the Philippines and China. The Philippine navy maintains a presence of less than a dozen navy personnel on the long Second World War US-built Philippine Navy landing craft BRP Sierre Madre (LT-57), which was deliberately run aground at the shoal in 1999 in response to the Chinese reclamation of Mischief Reef. The Philippines claims that the shoal is part of its continental shelf, while parts of the Spratly group of islands, where Second Thomas Shoal lies, are claimed by China, Brunei, the Philippines, Malaysia and Vietnam. In 2014, the Chinese government asked the Philippines to remove the grounded ship. Philippine supply ships subsequently 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 shoal on March 29, 2014 by sailing through shallow waters