Tax officers found more than 5kg of MDMA tablets on Wednesday while conducting routine operations at a location in Athlone.
Drugs worth an estimated €303,000 were found in a package that was headed for a Kildare address and had its origin in the Netherlands.
Investigations are ongoing.
This seizure is part of Revenue’s ongoing operations targeting the importation of illegal drugs.
Businesses or members of the public with any information regarding smuggling can contact Revenue in confidence on Confidential Phone Number 1800 295 295.