Luas Cross City will open for passengers on Saturday, December 9, the Herald can reveal.
Full tram services will operate from 2pm, allowing Christmas shoppers and commuters to travel from Cabra/Broombridge to the capital's main shopping areas of Henry Street and Grafton Street before carrying on to Dundrum.
Those keen to continue their shopping experiences will also be able to transfer to the Red line at O'Connell Street, continuing to Tallaght, or perhaps take in a show at the 3Arena, where Andre Rieu plays that night.
A spokeswoman confirmed full services will be running in just over four weeks' time, adding that the new service would form part of late-night services over the festive season.
"Luas is being delivered on time and on target after four-and-a-half years and in advance of the Christmas rush, so commuters, businesses and shops can all enjoy Christmas with the new service in place," the spokeswoman said.
Driver training is under way, and testing is continuing to ensure that services run smoothly.
Some works still remain to be done, including planting, which is likely to continue into the new year.
Luas Cross City will cost almost €370m and will extend the Green Line, which currently runs from Bride's Glen to St Stephen's Green.
It will continue for almost 6km to Broombridge, near Cabra, where it will connect with Irish Rail services to Maynooth, Longford and Sligo.
There is an interchange on O'Connell Street, where pass-engers can transfer to the Red Line, which runs to the Point Depot and on to Tallaght/Saggart.
Construction work began in July 2013, and 10 million passengers a year are expected to use the service.
It will take 21 minutes to travel from St Stephen's Green to Cabra, with 13 new stops along the route, eight of which are in the city centre.
The new system is designed to help reduce congestion and emissions from traffic and improve air quality.