Ashford Borough Council is owed more than £70,000 and Canterbury City Council is owed almost £45,000 in unpaid fines, BBC South East has found.
More than half of Kent's councils are using a private company to help recover fines issued to foreign drivers.
In Brighton more than three-quarters of fines were unpaid, a Freedom of Information request has found.
Brighton and Hove City Council told BBC South East it had issued 5,402 fines to foreign drivers, with 1,216 paid, and 3,400 remaining unpaid.  The council said it had written off the remaining 746 fines.
Most of those drivers fined in Kent were in tourist destinations in East Kent and near the Channel ports.
A private company called Euro Parking Collection has been hired by eight councils in Kent to work with Vehicle Licensing Authorities to collect some of the outstanding fines.
Illegal parking in the UK is a civil offence so councils cannot request drivers' names and addresses from their home countries.
In France and some other European countries however, illegal parking is a criminal offence dealt with by the police.
Patrick Troy from the British Parking Association said: "Local authorities don't have the means by which to enforce fines against foreign registered vehicles in the same way the do against UK registered vehicles.
"There is discrimination here and we've been arguing for some time that the government should work with colleagues in the European Union to negotiate reciprocal arrangements."
Foreign drivers owe south-east councils tens of thousands of pounds in unpaid parking fines issued in 2014-15.