Amboyna Cay, also known as An Bang Island,[by whom?] (Vietnamese: Đảo An Bang, Chinese: 安波沙洲; pinyin: Anbo Shazhou, Malay: Pulau Amboyna Kecil; Tagalog: Lagos) and other names is an island of the Spratly Islands group in the South China Sea located just outside (SW) of the southwest of Dangerous Ground. It is SW of Barque Canada Reef, south of the London Reefs, and NW of Swallow Reef.
The island has two parts: the east part consists of sand and coral, and the west part is covered with guano. It has a fringing reef. An obelisk, about 2.7 m high, stands on the SW corner. There is little vegetation. It is described by some as heavily fortified. A lighthouse has been operational on the island since May 1995.
In 1982, a Singapore yacht operated by the owner and his wife transporting four German hams on a DX-pedition to Amboyna Cay was fired upon by Vietnamese forces. One of the hams, Diethelm Mueller, was hit by an artillery round and fell overboard. The yacht burned and the rest of the party drifted for 11 days on debris. Another ham, Gero Band, died of thirst the day before the survivors were rescued by a passing Japanese freighter which took them to Hong Kong.