Retail outlets across the country opened their doors today for the post-Christmas Day sales.
For the first time, 70% of retailers in urban areas opened for business on St Stephen's Day.
Retailers reported long queues outside their premises this morning.
Clothing retailer Next opened its doors at 6am.
Retail Ireland says that retailers expect consumers to spend millions of euro in shops around the country in the post-Christmas sales.
They are hoping for an increase in sales compared to last year.
In Dublin, Arnotts reported a double digit increase in sales today compared with St Stephen's Day last year.
Meanwhile, Brown Thomas say sales have been "really strong" though can not give exact figures or comparisons.
It follows a busy pre-Christmas shopping period - retailers reported a 2% to 2.5% increase in sales last weekend compared with the same period last year.
Mild weather, improved consumer confidence, and an increase in shoppers travelling from Northern Ireland, as well as the fact that Christmas Day fell on a Tuesday, are credited with causing the boost.
People travelled to St Stephen's Day sporting and cultural events.
A Sunday service is operating on Dublin Bus routes, with the Luas running until 11.30pm.
There are no rail or DART services in operation today.
Bus Éireann's Expressway services, and commuter services including in the greater Dublin, Cork and Limerick areas operated on a reduced timetable.