The single-vehicle cash took place about 3.30pm as the motorcycle taxi rider carried the three men along the west coast road towards Patong.
He failed to negotiate the deep valley near the Naka Resort and the motorcycle and its human cargo plunged into a ditch.
Rescuers patched up the rider and his three passengers and took them all to Patong Hospital.
They were all treated and allowed to leave.
The rider is likely to face dangerous driving and driving while overloaded charges.
Travel insurance for tourists has become a hot topic among envoys because uninsured tourists and expats sometimes leave bills unpaid after being treated at Phuket's public hospitals.
The issue is likely to be aired again when the holiday island's honorary consuls meet Phuket's governor at their monthly meeting on December 17.
However, the barrier to compulsory travel insurance has always been that introducing such a scheme would make Phuket and Thailand more expensive than rival destinations within the region.
Thais travelling to Europe must have travel insurance.