More than 540 litres of wine, beer and spirits was seized at Dublin Port over the weekend and this morning.
Revenue discovered the alcohol in a van and two trucks that had disembarked ferries from the UK.
The three drivers - all men in their 30s and 40s - have been questioned in connection with the seizures.
The alcohol seized had a total value of more than €6,000, and represents a potential loss to the Exchequer of over €3,000.
In a statement, Revenue said: "These seizures are part of Revenue's ongoing operations targeting the supply and sale of illegal alcohol in the shadow economy."