Capt Kraisorn Boonprasop of Thalang Police was notified of the accident, opposite Hoi Sab Restaurant on Srisoonthorn Rd in Thalang, at 5:15am.
Rescue workers arrived at the scene to find a white Honda motorbike in the 1.5-metre-deep ditch on the side of the road.
The driver, later identified as Pisanukarn Sasilaksanakun, was unconscious with serious head injuries.
He had also suffered serious injuries to his neck and right knee, rescue workers reported.
“The man was taken to Thalang Hospital and then transferred to Vachira Phuket Hospital in Phuket Town for a brain scan,” one rescue worker said.
Police confirmed they are still investigating the incident and checking CCTV in the hope of determining the cause of an accident.
There was no mention of whether or not Mr Pisanukarn was wearing a helmet at the time of the accident or whether police suspect alcohol was involved.