with, as of August 2024, a strength of 1,456 out of an established strength of 3,869, and the Naval Service Reserve (NSR), with a strength of 97 out of an established strength of 200.

The RDF was established on 1 October 2005 and replaced the Second Line Reserve, previously named An Fórsa Cosanta Áitiúil (FCÁ) in the case of the AR, and An Slua Muirí in the case of the NSR. The Reserve has undergone significant reorganisation and modernisation in tandem with the Permanent Defence Forces