They were found during a search over the weekend.
Gardaí have arrested a man in his 40s following the seizure of four explosive devices in Ronanstown.
They were found during a search of a van on Sunday afternoon.
The devices were viable and the Army Bomb Squad was called in to make them safe.
A scrambler bike and a small amount of cannabis were found in follow-up searches in Ballyfermot and Ronanstown.
In a statement, gardai said:
"At approximately 3:40pm, a van was searched by Gardaí in the Ronanstown area where four viable improvised explosive devices were seized.
"A male (40s) was arrested in connection with the incident, and he is currently detained under Section 30 of the Offences against the State Act, 1939, at a Garda station in the Dublin area.
"The Defence Forces Explosive Ordnance Disposal (EOD) team was requested to attend and safely removed the explosive devices.
"During subsequent searches in the Ballyfermot and Ronanstown areas, a small quantity of suspected cannabis and a scrambler bike were also seized.
"All drugs seized are now subject to examination by Forensic Science Ireland."
