The cars were parked outside Goldthorpe police station, Barnsley, when they were torched in the early hours of this morning.
Officers were alerted to the blaze at 2.10am and discovered that the flames had also caused some damage to the side of the police station and a council van.
POLICE: Two fatal stabbings in Sheffield remain unsolvedFirefighters dealt with the blaze.
The station and damaged cars were cordoned off this morning.
Three Barnsley men, aged 18,33 and 35, were arrested on suspicion of causing criminal damage and arson and remain in custody this morning.
Over the weekend a derelict building was set alight on High Street, Goldthorpe.
Firefighters were called out to deal with the blaze at 7.50pm on Saturday.
Chief Inspector Mark James, from Barnsley, said: “This reckless incident has left two operational police cars extensively damaged and behaviour like this will not be tolerated.
“Thankfully, no one was injured but the fire has also caused damage to the side of the police station and a council van.
“Officers worked quickly after the incident to carry out enquiries and these enquiries are continuing today.”
Anyone with information is asked to call 101 quoting incident number 56 of 1 April 2019 or call Crimestoppers anonymously on 0800 555111.