Update 10 p.m.
The fire at the Oceano Dunes has been put out, Cal Fire said.
The fire was a quarter-acre in size when it was contained within the dunes at around 9 p.m.
There is no damage recorded from the fire at this time.
Cal Fire responded to a call at around 5 p.m. using fire engines, hand crews, a helicopter and a spotter plane. Cal Fire was assisted by Five Cities Fire.
Cal Fire is investigating how the fire began.
Update 7 p.m.
Cal Fire said it has stopped the fire from spreading.
Cal Fire is reporting a quarter-acre vegetation fire in the Oceano Dunes State Vehicular Recreation Area.
The fire was spreading at a slow rate and not threatening any structures, according to a tweet by Cal Fire San Luis Obispo
Cal Fire said a helicopter is dropping water on the Dunes Fire.