The 46-year-old man may have missed the turn to the right from Viset Road into Rawai Beach Road and continued on to his death.
Injured in the spectacular crash was the man's Philippina girlfriend, who is now in Vachira Phuket Hospital in Phuket City.
The crash startled locals about 5.30am. Viset Road comes to an abrupt end near Rawai's sea gypsy village and even locals are sometimes caught unawares by the sharp right-hand turn.
Low tide and daylight revealed the crumpled silver car on the sand. It appeared the driver was alert enough to avoid a large memorial in front of Rawai pier but sideswiped a neighboring sala at speed and kept right on going into the sea.
It is not known at this stage whether the man died from the impact of the crash into the sea or drowned. Police believe he may have been drinking and unfamiliar with the road.
Phuketwan has the man's name but will not publish it because relatives have yet to be notified by Swiss envoys.
An out-of-proportion number of expats and tourists die on the roads on Phuket and in Thailand, mostly in motorcycle crashes.
The latest statistics available show that 119 people died on Phuket's road's in 2011. Thousands of other foreigners and locals are crippled and maimed in motorcycle crashes.
No figures have been released for 2012. The latest official Phuket monthly update on the Phuket road toll was for April last year.
No updated figures have been released since then.
No updated figures have also been released for drownings on Phuket - which mostly involve tourists - since then.