Divers from Khao Lak Scuba Adventures found the body of Zhang Lin near Koh Bon, off Kuraburi in Phang Nga, at about 2:30pm.
Officials from the Similan National Park outpost in Kuraburi notified Marine Police that her body had been found at 7pm last night (Nov 27).
Police said that, according to the divers who found her, Ms Zhang was floating face-down without her mouthpiece in place.
They brought her body on board their dive boat, the Taisiri, and performed CPR (cardio-pulmonary resuscitation) in an attempt to revive her. However, Ms Zhang remained unresponsive.
A speedboat sped Ms Zhang ashore and she was rushed to Tai Muang Hospital, but doctors there said that she died at least six hours before her body was discovered.
However, doctors also said they would request that an autopsy determine her cause of death.
Photos presented to The Phuket News show a cut over Ms Zhang's left eye and minor abrasions on her forehead.
Ms Zhang was with friends on a liveaboard dive tour on the MV Peterpan, operated by the Similan Seven Sea Club dive company based in Khao Lak, said Lt Col Chakri Maigumponsuth of the Phang Nga Marine Police
“However, we are still investigating the nature of the incident,” he said.
Police have notified the Chinese Embassy of Ms Zhang’s death, he added.
“Together with Tai Muang Police, we will question the owner of the Similan Seven Sea Club dive company, Tongkan Worapanya, 39, and check all documents related to the diving contract involving the victim,” Col Chakri said.
The Similan Seven Sea Club told The Phuket News that the company would release a statement about the incident later this afternoon (Nov 28).