The accident took place at the Rawai pier in Muang district on Saturday morning.
A preliminary investigation suggested that Stefan Braunwalder, 47, was driving at high speed and went straight on at the bend where Rawai Pier meets the land.
The car ploughed through two motorbikes and partly demolished a sala at the landward end of the pier before plunging off the sea wall and landing upside down.
Villagers were able to rescue the victim's Filipino girlfriend, 27-year-old Ronalyn Coralda from the vehicle, basically unhurt, but Mr Braunwalder is believed to have died instantly in the crash.
Pol Lt Col Jaruth Ployduang Chalong Police Station told The Phuket News, “They had been drinking in various restaurants. His girlfriend urged him to rest before going back to the hotel in Patong.
"But because it was 5 am he wanted to go back to their hotel in Patong. Instead of going via the Chalong intersection, he decided to drive through Rawai and along the coast road.
"At the bend near the pier he went straight on."