The measures will also apply if you're travelling from Great Britain but not Northern Ireland.
Anyone traveling to Ireland from overseas will have to show a negative Covid test from Friday.
They either need a negative PCR test within 72 hours before arrival, or a professional antigen test 48 hours before coming here.
The measures will apply to Great Britain but not to travel from Northern Ireland.
Laws enabling the return of mandatory hotel quarantine will also be brought before the Oireachtas this week.
Taoiseach Micheál Martin has also urged everyone to reduce their social contacts.
Parents will be asked to ensure their kids have only one social activity outside of school a week. Mask wearing is also likely to be advised for all kids over 9.
The new measures are being implemented amid fears over the Omicron variant. From today in England, laws are in place to ensure the wearing of face covering in shops and on public transport.
