Police arrived at the school with Ruamjai Kupai rescue workers at about 11am to find a Honda City on its roof near the school fence.
The driver, Narongrit Nontanit, had suffered injuries to his right leg and chest and was rushed to Mission Hospital Phuket in Rassada.
Nearby was a blue Ford Fiesta with damage to its front and front-right panel. The driver, Tina Marie Cummings, 51, a teacher at the school, suffered no injuries in the collision.
Ms Cummings told police that while she was making a turn into the school, the Honda approached at high-speed and slammed into her vehicle before flipping onto its roof beside the road.
“Both vehicles were taken to Wichit Police Station while we are waiting to question the injured victim. No charges have been filed yet,” said Lt Thapanee Warinsaard of the Wichit Police.