Police officers from Doncaster West Neighbourhood Policing Team were on duty in the Skellow and Woodlands areas when they sprang into action to seize the bikes.
A spokesman said: “Sometimes you are just in the right place at the right time.
"A green off road bike was seized yesterday from the Skellow area. Then today a suspected stolen pit bike was recovered from the Woodlands area, thanks to information from a member of the public.”
Anyone wanting to report off-road bikes and nuisance caused by them and their riders in Doncaster and across South Yorkshire can contact South Yorkshire Police on 101.
Alternatively, in an emergency, call 999 or you can report information to independent charity Crime Stoppers on their dedicated reporting hotline in confidence on 0800 555 111.