Joyriders smashed up three buses after going on the rampage in a Park and Ride car park.
Staff at Preston Bus discovered the damage to their vehicles on Tuesday morning when the site at the Capitol Centre, Walton-le-Dale (pictured) was reopened, having been closed on Sunday and Bank Holiday Monday.
Police said those responsible were believed to have driven the buses around the site recklessly.
Now investigations are underway to find the culprit or culprits, with members of the public asked for their help.
A spokesman for Preston Bus said: “We can confirm that unfortunately an act of unwarranted vandalism occurred.
“We have contacted police and they are working to gather CCTV and forensic evidence.
“Preston Bus believes this was a targeted act by an adult, and not the result of mindless actions of youths.
“Any information regarding the perpetrators should be passed to the police.”
It is not known how badly damaged the buses were in the incident, or whether they will have to be taken out of service. It is not thought the Park and Ride service has been affected.
A spokesman for Lancashire Constabulary confirmed the incident had been reported, but no arrests have been made.
A spokesman for the force said: “It appears that a person or a group of people have gained entry to the buses and driven them around and caused damage. No arrests have been made and enquiries are ongoing.”
Anyone with informationabout the matter is asked to call police on 101 quoting log reference 571 of May 2.