Darren Polean, 42, from Lightown in Drumbaragh and Brian Walsh, 34, from Culmullen in Drumree, appeared at Belfast Crown Court on Thursday.
Barristers for both men asked that they be re-arraigned on offences.
They had initially faced, and denied, four charges.
After pleading guilty to two offences, the remaining two charges faced by Polean and Walsh were left on the books, not to be proceeded with.
Both pleaded guilty to a charge of possessing an explosive substance with intent to endanger life or cause serious injury to property on 6 October, 2015.
They also admitted a charge of possessing articles for use in terrorism, on the same date, "in circumstances which give rise to a reasonable suspicion that their possession was for a purpose connected... to the commission, preparation or instigation of an act of terrorism".
The articles in question included a Satellite Navigation System, bolt cutters, a balaclava, binoculars, assorted gloves, hand-held two-way radios, disguises, a head torch and plastic adhesive tape.
A Crown barrister told the judge that the pleas "satisfied the interests of justice" and agreed to leave the remaining two counts on the books, possessing explosives in suspicious circumstances and conspiring to cause an explosion.
Walsh's legal representative told the court she was seeking both a pre-sentence report and a medical report ahead of sentencing.
Both men were remanded in custody.
Two men from County Meath have admitted terrorist offences linked to the discovery of a bomb at a Londonderry hotel which was due to host a PSNI recruitment event in October 2015.