The incident happened on the A630 Sheffield Road just outside Conisborough, near Doncaster, at 17:00 BST on Saturday.
South Yorkshire Police said officers were called to the scene after reports that a motorbike had left the road north of Archers Way.
The force is appealing for any witnesses to contact them.
A 25-year-old man from Doncaster has died following a motorcycle crash in South Yorkshire.