The vice-mayor of Tallinn said that passengers on public transport should go to jail for ten days if they do not buy a ticket and then fail to pay a 600-kroon (£30) fine.
A lack of resources means the city has few ticket inspectors.
The city of Tallinn wants to throw passengers who don't buy bus and tram tickets behind bars.
Vice Mayor Jaanus Mutli said passengers caught without tickets could face a minimum 10 days in jail if they fail to pay the 600-kroon fine (USD58,00 ; EUR 39,00) currently levied for the violation.
"We want to send a message to all those who find it acceptable to travel at someone else's expense," Mutli said in a statement, stressing that current legislation says the offense is punishable with jail time.
It's easy to ride for free on Tallinn's public transportation system because passengers do not need to present tickets upon entering buses, trolleys and trams. A limited number of controllers make random checks.
Some 25,000-30,000 "rabbits" — the nickname for passengers without tickets — are caught every year in Tallinn.
Three years ago, the city started publishing the names of "busted rabbits" on the Internet. The attempt at public humiliation, however, failed to work, as many of those caught refused to pay the fines or repeated the violation.
"Imprisonment is, naturally, meant be the last resort when all other options have been used," Mutli said.
Mart Moosus, Tallinn city's chief economist, said the city loses up to 30 million kroons (US$3 million; €2 million) annually for unsold tickets and unpaid fines — enough to buy 15 new buses.
A one-way ride on Tallinn's public transport system costs 10 kroons (US$1; €0.70), though most passengers download a monthly ticket to their electronic ID cards or use a SMS ticket in this tech-savvy Baltic nation.