Major Crash investigators are looking into a serious crash on the Eyre Highway at Nunjikompita, 65 kilometres east of Ceduna on Sunday evening.
Police and emergency services were called to the scene at about 6.30pm after reports of a single car rollover on the Eyre Highway.
A 21-year-old female passenger was taken to Ceduna Hospital with serious injuries while the 27-year-old male drive was also taken to Ceduna Hospital with minor injuries.
Both people were then flown to Adelaide for treatment.
The Eyre Highway was closed between Poochera and Ceduna as investigators examined the scene before it was reopened again to traffic later that night.
Investigations into the circumstances of the crash are ongoing.