Petley Reef (); Núi ThỠReef (); Mandarin , is a reef on the northern part of the Tizard Bank of the Spratly Islands in the South China Sea. The reef has been occupied by Vietnam since 1988. It is also claimed by China (PRC), the Philippines, and Taiwan.
The Vietnamese Navy is stationed on a complex of structures called Thá» Island, with geographical coordinates recorded on the sovereignty marker as 10ð24â²40â³N 114ð34â²48â³E. This military outpost is connected by a bridge to a multi-purpose cultural center completed in December 2018.
Starting in June 2025, Vietnam began land reclamation activities at Núi ThỠReef.