Ladd Reef

Ladd Reef (Vietnamese: Đảo Đá Lát; Mandarin Chinese: 日積礁/日积礁; pinyin: Rìjī Jiāo) is a Vietnam-controlled reef in the Spratly group of islands, South China Sea. China (PRC) and Taiwan (ROC) are also claimants of the reef. Like Spratly Island, Ladd Reef lies to the west of the Philippines-defined "Kalayaan Islands" claim area.^[1]

Ladd Reef

Disputed reef
Ladd Reef and Da Lat Island
Ladd Reef
Other names	Đá Lát (Vietnamese) 日積礁 / 日积礁 Rìjī Jiāo (Chinese)
Geography
Location	South China Sea
Coordinates	8°39′57″N 111°40′36″E
Archipelago	Spratly Islands
Total islands	1
Major islands	Da Lat Island
Area	0.55 km2 (0.21 sq mi)
Administration
Vietnam
District	Trường Sa District
Township	Trường Sa Township
Claimed by
China
Taiwan
Vietnam

Names

The English name Ladd Reef was coined by Richard Spratly in late March 1843, after Captain Ladd of the ship Austen, who seemed to be the first to have seen the reef.^[2] The Chinese name Rìjī Jiāo was coined in 1947 to replace the 1935 name Lādé Jiāo (拉德礁),^[3] which was transliterated from the English name Ladd.

Geography

Ladd Reef lies west of Dangerous Ground in the western half of the Spratly Islands, to the south of Coronation Bank, southwest of West London Reef (West Reef) and 15 nautical miles (28 km; 17 mi) west of Spratly Island.^[4]

This coral reef lies on a northeast-southwest axis, 3 nautical miles (5.6 km; 3.5 mi) in length, 1 nautical mile (1.9 km; 1.2 mi) in width, and spans over an area of 9.9 square kilometres (990 ha; 2,400 acres; 3.8 sq mi). It is entirely submerged during high tide, but there are some stones jutting out of the sea during low tide.^[5]

Da Lat Island (Đảo Đá Lát)

Before the land reclamation, Da Lat Island consisted of a permanent house on the right and a multifunctional cultural house on the left. The sovereignty marker was placed at the durable house.

Da Lat Island, formerly known as Da Lat Islet, is the only islet situated on a coral reef. Initially, a permanent house was constructed on the island to serve as a station for the Vietnamese Navy. In 2018, a multifunctional cultural house was built there and was completed in October of the same year.^[6]

The geographical coordinates of this island, as recorded on the sovereignty marker, are 8°40′10″N 111°40′23″E (or 8.66944°N 111.67306°E). This location places it within the strategic and ecologically significant region of the South China Sea.

In early November 2022, Vietnam began land reclamation and renovation to transform Da Lat Islet into Da Lat Island.^[7] As of March 2025, Da Lat Island has an estimated reclaimed land area of around 55 hectares, stretching approximately 2.4 kilometers in length, with the potential for an airport to be constructed there.^[8]

Structures

The reef is uninhabited but contains a Vietnamese lighthouse (built in 1994)^[9] with the inscription Hải đăng Đá Lát^[10] (literally "Ladd Reef Lighthouse"). The lower portion of the lighthouse consists of quarters for a handful of Vietnamese soldiers and the lighthouse keeper.

Other information

In 1945, towards the end of the Second World War, a Dutch submarine (HNLMS O-19) ran aground on Ladd Reef.^[11]