Third Thomas Shoal, known as Banko Thomas in the Philippines, Bãi Đồng Cam in Vietnam, and 和平暗沙 in China, is a reef in the north-west of the Spratly Islands in the South China Sea.

It is located 7.5 nautical miles (13.9 km; 8.6 mi) north of Flat island, and 73 nautical miles (135 km; 84 mi) north of Mischief Reef.

The reef is one of three martnamed after Thomas Gilbert, the captain of the Charlotte: