A car found burning on St John’s Green, Kimberworth Park, Rotherham, had been deliberately set alight.
The arson attack was reported to firefighters at 3.10am on Saturday.
They found a Fiat Punto engulfed in flames.
That night firefighters were also called to Psalter Lane, Holmes, Rotherham, to another car found alight.
The vehicle had been torched.
A car fire dealt with by crews on Dovercourt Road, Masbrough, Rotherham, at 8.50pm on Saturday was down to a mechanical fault, but another car found burning on Hastilar Road, Richmond, Sheffield, was the result of an arson attack.
South Yorkshire Police was informed of the arson attacks.
Anyone with information should call 101.