Tyres we set alight on the playing fields around Aston Academy, Aughton Road, Swallownest.
They were found burning at 8.30pm on Monday.
Firefighters were called out to deal with the blaze.
They also dealt with a shed which was set alight in another arson attack on Doles Crescent, Royston, Barnsley.
Emergency services were alerted to that blaze at 7.20pm that night.
n Anyone with information should call South Yorkshire Police on 101 or Crimestoppers on 0800 555111.