A teenager has been killed and another injured after a collision between a quad bike and a motorbike at Buffalo Beach just north of Australind overnight.
The two 19-year-old men went riding yesterday afternoon and the teenagers' family notified police after they failed to return home.
They were last seen by fishermen at 5pm.
The RAC Rescue helicopter was sent to search the area and found the pair at about 5.30am today.
A police spokeswoman said it appeared there had been a collision between the two bikes.
One of the teenagers was deceased and the other was badly injured.
The injured man was taken to Royal Perth Hospital by the helicopter.