Gardaí from Ronanstown Garda Station became aware of an attempt to carry out a drone delivery to a prison on Sunday.
Gardaí subsequently carried out a search of a residential property under warrant in west Dublin as part of ongoing operations targeting the supply of controlled substances into prisons in the area.
During the search, a drone and a number of electronic devices were seized.
Follow-up searches were conducted in south-west Dublin, and a vehicle was seized.
Four adult males, aged in their late teens, 20s, 30s, and 40s, were arrested and detained under Section 4 of the Criminal Justice Act 1984 at Garda Stations in the Dublin Region.
All four males have since been released without charge. A file will be prepared for the Director of Public Prosecutions.
Gardaí said investigations are ongoing.
