They only have until the end of the year to exchange their licence.
Up to 10,000 people who are living in the Republic and driving on a Northern Irish or UK drivers licence have still not applied to exchange it.
They are being reminded that their existing licence will not allow them to drive here after December 31st.
More than 60,000 of these drivers have applied to swap their licence for an Irish once since 2019.
The Road Safety Authority's Brian Farrell says it's vital that all affected drivers get a valid driving licence urgently.
''They need to exchange it immediately as their UK, Northern Ireland driving licence will not be valid to drive here after the 31st of December'', he said.
''The mechanism that allows for European countries to exchange each other's licences expires on the 31st of December.
''If you're living in Ireland and you hold a UK licence, you will no longer be able to drive on that licence after that date''.