I wish to advise that Irish driver licensing operates within a framework of EU law, which sets out the driver licensing legislation with which all Member States must comply. Licence formats, vehicle categories and driving test standards are all set at EU level. As all Member States test drivers to the same standards, there can be mutual recognition of driving licences.
Someone who is resident in Ireland must hold an Irish or EU/EEA driving licence to drive here. A visitor to Ireland can use a non-EU/EEA licence during their visit, provided it is current and valid, but on taking up normal residence here they must exchange their licence or apply for an Irish licence.
A driving licence may be exchanged for an Irish licence where Ireland has a driving licence exchange agreement with the other jurisdiction. A person with a full but non-exchangeable licence must go through the normal driver learning process, but can avail of shorter Essential Driver Training of 6 lessons, instead of 12, and does not have to be a learner for the usual minimum of 6 months before taking a driving test.