List of deepest dive sites in the Gulf of Thailand

The Gulf of Thailand, historically known as the Gulf of Siam, is a shallow inlet^[1][2] adjacent to the southwestern South China Sea, bounded between the southwestern shores of Mainland Southeast Asia and the northern half of the Malay Peninsula. The gulf's many coral reefs have made it attractive to divers visiting Thailand.

The highest concentration of deep technical dive sites is in the Samae San Island area. It offers a range of the deepest technical dives in the Gulf of Thailand that are also easily accessible^[3]. A number of deep wreck dives are present in the Gulf of Thailand however these require extended boat trips and extra safety and logistical considerations. Koh Tao offers two easily accessible tec diving sites however these have much shallower depth compared to other tec diving locations in the Gulf of Thailand

Name	Max. depth	Coordinates	Location	Type of Dive
Samaesan Hole[4][5]	100–85 m (328–279 ft)	12°32.314′N 100°57.616′E / 12.538567°N 100.960267°E / 12.538567; 100.960267	Samae San Island	Open ocean
Sharkfin Deep Drop / Samaesan Cliff [4][5]	85–50 m (279–164 ft)	12°31.705′N 100°56.020′E / 12.528417°N 100.933667°E / 12.528417; 100.933667	Samae San Island	Open ocean / Wall
1/4 Mile Mouthpiece Drop[5]	75 m (246 ft)	12°30.094′N 100°57.233′E / 12.501567°N 100.953883°E / 12.501567; 100.953883	Samae San Island	Open ocean
Tattori Maru[6]	75 m (246 ft)	9°58.00′N 101°05.00′E / 9.96667°N 101.08333°E / 9.96667; 101.08333 [7]	120 nmi (220 km; 140 mi) east of Koh Tao	Wreck
Drillship Seacrest[6][8]	73 m (240 ft)	08°3.806′N 101°39.433′E / 8.063433°N 101.657217°E / 8.063433; 101.657217[9]	170 nmi (310 km; 200 mi) northeast of Songkhla	Wreck
USS Lagarto[6]	70 m (230 ft)[10]	7°55′N 102°18′E / 7.917°N 102.300°E / 7.917; 102.300[11]	Ko Losin	Wreck
Thunder Bowl[5]	65 m (213 ft)	12°32.807′N 100°55.655′E / 12.546783°N 100.927583°E / 12.546783; 100.927583	Samae San Island	Open ocean
HTMS Pangan[6]	65 m (213 ft)	No record	60 nmi (110 km; 69 mi) northeast of Koh Tao	Wreck
Narcosis Colosseum[5]	50 m (160 ft)	12°30.128′N 100°57.191′E / 12.502133°N 100.953183°E / 12.502133; 100.953183	Samae San Island	Open ocean
Koh Rong Nang Training Buoy[5]	50–37 m (164–121 ft)	12°32.968′N 100°57.298′E / 12.549467°N 100.954967°E / 12.549467; 100.954967	Samae San Island	Reef
HTMS Sarasin[12]	43 m (141 ft)	No record	Pattaya	Wreck
PAK 1/Koho Maru-5[13]	43 m (141 ft)	12°05.504′N 101°40.931′E / 12.091733°N 101.682183°E / 12.091733; 101.682183	Koh Chang	Wreck
Chumphon Pinnacle[14]	40 m (130 ft)	10°10.350′N 99°46.722′E / 10.172500°N 99.778700°E / 10.172500; 99.778700	Koh Tao	Reef
Sail Rock/Hin Bai[15]	40 m (130 ft)	9°55.615′N 99°58.618′E / 9.926917°N 99.976967°E / 9.926917; 99.976967	Koh Tao	Reef