Irish driving licences can only be issued to people resident in Ireland. Driving licences issued by the Member States of the EU are mutually recognised. Therefore, a holder of an Irish licence who moves to another Member State can drive on that licence until the licence expires. On expiry, the licence holder will then need to exchange their Irish licence for the licence of the country they are now resident in.
After 31 December 2020, the UK will no longer be a Member State and so a UK driving licence will not be recognised here. Unless a licence exchange agreement has been put in place with the UK, the holder of a UK licence who takes up residence in Ireland will be obliged to apply for a learner permit and undergo driver training before passing the driving test in order to be issued with an Irish licence.
Ireland will pursue a licence exchange agreement with the UK after the transition period has ended i.e. after 31 December 2020. This option will involve a formal agreement with the UK and legislation here in Ireland.