The Luas Cross City Line in Dublin will open to passengers on Saturday, December 9.
It will see an extension of the current Green Line from St Stephen's Green through O'Connell Street and towards Cabra and Broombridge.
Construction first started on the €370m project in June 2013.
Head of Public Affairs with Dublin Chamber Graeme McQueen says it's a relief to city centre businesses.
"It has been a long five years for businesses in the city centre, but it is fantastic to see that the line will open on-time and in advance of Christmas," he said.
"The weeks preceding Christmas are hugely important for Dublin retailers.
"The opening of the Luas Cross City extension provides shops and businesses in the city with a huge boost."
The Chamber, which represents more than 1,300 businesses in Dublin, said the completion of the project would provide a major boost to city centre retailers ahead of the crucial Christmas period.
“The extension of the Luas network through the heart of the city and out to Cabra will be a fantastic addition to the city's transport network," said Mr McQueen.
"Constructing the new line has been a complicated task and has resulted in significant upheaval over the past five years.
"But the city will reap the benefits of the new line for decades to come."