A speedboat packed with tourists slammed into a concrete post off the coast of Thailand, injuring at least 36 people — and officials say the boat’s captain may have dozed off shortly before the horrific crash.

Thirty-nine people — including visitors from Russia, Kazakhstan and China — were aboard the Thanathip Marine 555 when it struck a channel marker less than a half-mile from shore in the Chalong Bay on Wednesday, the Bangkok Post reported. 

Photos show the destroyed bow of the boat resting against the marker as rescue crews helped dazed, bloodied passengers to the pier.

The group — which also included the boat’s driver, a tour guide and the driver’s assistant — was headed back from the Phi Phi islands when the crash occurred, the outlet reported.

Police are investigating whether the boat’s operator, Sathit Matchai, may have fallen asleep, and are awaiting test results on his blood-alcohol level.

“I don’t know how the crash happened. The boat was driving normally, and suddenly there was a loud noise that jolted us,” one shocked survivor, a Thai national, told ViralPress.

Authorities say six people were being treated for broken limbs, while others were rushed to Phuket hospitals with less serious injuries.

Each injured survivor is entitled to $440 insurance, the outlet said.

“Ten of them were admitted to the Vachira Phuket Hospital, nine were sent to the Dibuk Hospital, five to the Bangkok Hospital Siriroj, two to the Bangkok Hospital Phuket, five to the Mission Hospital Phuket, and two to the Phuket Provincial Administrative Organisation Hospital,” Phuket Governor Narong Woonciew said.