Thousands of commuters will be driving home for Christmas - or hopping on the nearest train - today as the country is once again opened for travel.
Up to 20,000 passengers are expected to board intercity rail services from today and daily up until Christmas Eve, as Covid-19 restrictions on inter-county travel are lifted.
AA Ireland expects to see a "flurry of movement" on Irish roads.
The motoring group said it could not forecast exactly how many vehicles will be on the road, but it did say traffic volumes had "increased significantly" with the previous lifting of restrictions.
In the week beginning December 7, 436,699 vehicles took to the road - a 3pc increase on the previous week.
Conor Faughnan, director of consumer affairs at AA Ireland, said: "2020 has been a funny old year, but we've seen when restrictions have been lifted that traffic has increased significantly.
"Therefore, I expect as the countrywide travel ban is lifted, we'll see a flurry of movement."
Mr Faughnan said he expected interurban motorways to be "much busier".
Ordinarily, Christmas commuters would drive across the country on December 23 or 24.
However, due to the large number of people working from home, it is expected more drivers will make their journeys today and across the festive period.
Irish Rail said up to 50pc of all capacity had been booked.
"As it stands, we're expecting numbers to increase," said Barry Kenny, corporate communications manager with Irish Rail.
It is expected around 20,000 will board intercity rail services each day throughout the festive period.
Passengers should also keep in mind that trains are travelling at half-capacity, due to Covid-19 restrictions.
"We must stress to intending customers that pre-booking is mandatory for intercity rail for journeys between December 18 and January 6 - the period for which non-essential inter-county travel is permitted," Mr Kenny said.
The company said it expects to reach "peak demand" by next Wednesday, December 23, according to bookings.
Tomorrow "looks like the busiest day this weekend", Mr Kenny added.
The Dublin-Cork route is forecast to be the busiest one for the company.
Bus Éireann said it has "no indication of a major shift in demand expected this weekend", but its services have been "steady over the last number of weeks".
More passengers will travel by ferry today and tomorrow than on the same days last year.
1,147 passengers from Holyhead and Fishguard in the UK will travel via Stena Line today.
Only 983 people travelled with the company on December 18 last year. Another 1,198 will travel from the UK to Ireland with Stena tomorrow.
However, overall passenger numbers have dropped significantly when compared to last year across the weekend and closer to Christmas.
On Sunday, only 887 passengers will travel via Stena Line compared to the 2,328 people who travelled last year on the same date.
Dublin Airport said passenger numbers will be down 88pc over the Christmas period compared to the same period last year.