At 5:50pm Tha Chat Chai police were called to the scene of an accident where a motorcycle had crashed into the back of a parked SUV.
Police arrived at the scene with Kusoldharm rescue workers and found a wrecked Honda Wave lying on the road next to a Mitsubishi SUV.
The body of the dead five-year-old boy and an unconcious teenager were lying on the road.
The injured boy, who had suffered a broken arm, was later identified as Chanakorn Cheirlangsard, 16, from Takuatung in Phang Nga.
Chanakorn received first aid at the scene before being taken to Vachira Phuket Hospital.
The body of the five-year-old, named as Warayuth Prarisake, also from Takuatung, was taken to Thalang Hospital.
When questioned by police, the driver of the Mitsubishi, Isamael Madrare, 42, from Satun said that he had parked his truck on the bridge to enjoy the view and the motorbike slammed into the back of his truck.
Mr Isamael was taken to Tha Chat Chai police station for further questioning.