A woman in her 40s has been flown to hospital after crashing a quad bike on Flinders Island.
Tasmania police said the woman and her passenger were not wearing helmets when she lost control of the vehicle after midnight on Sunday.
The quad rolled over and the woman suffered serious injuries to her upper body.
The passenger was not injured.
The woman was flown to Launceston General Hospital in serious but stable condition by the Royal Flying Doctor Service.
The investigation into the cause of the crash continues.