The car crashed into a ditch on a dangerous, winding stretch of the road north of Kalim.
The Toyota Vios, heading towards Kamala, ended in the ditch on the opposite side of the road about 6.10am.
Kusoldharm Foundation paramedics took the man's body to Patong Hospital. A nurse said that friends of the man had been notified.
It's not known whether he was wearing a seatbelt.
On Thursday, at a meeting with Phuket Governor Governor Maitree Inthusud, Patong Deputy Mayor Chairat Sukban listed this stretch of road as especially dangerous because the painted central line had worn away.
He also said the coast road stretch south between Patong and Karon was unsafe at night because street lighting had failed and was yet to be replaced.