A red Mitsubishi Magna sedan was travelling south on Indian Ocean Drive. About 2 kilometres north of Old Yanchep Road, the Mitsubishi crossed onto the incorrect side of the road and collided with a black Holden Colorado before hitting a silver Nissan Pathfinder.
The 23 year old male driver of the Mitsubishi and the 49 year old male driver of the Holden were not injured.
The 48 year old female driver of the Nissan was injured and taken to hospital for treatment.
Investigating officers are asking anyone who saw the crash or the red Mitsubishi Magna prior to the crash to call Crime Stoppers on 1800 333 000 or make a report online at www.crimestopperswa.com.au