Adelaide had city Boxing Day trading for the first time when stores in the Rundle Mall precinct opened at 11:00am.
Retailers are pleased with changes which bring Adelaide into line with most of the other Australian capital cities.
Legislation passed earlier in the year declared Rundle Mall a tourist precinct and able to trade on December 26.
The Rundle Mall Authority said it expected about 700 retailers across 15 arcades and the Mall itself would trade.
Rundle Mall CEO Ian Darbyshire welcomed the changes to retail trading.
"South Australia has waited a long time for this opportunity," he said.
"We anticipate Rundle Mall to be a hive of activity with over 120,000 visitors heading to the precinct." Trader Brenton Whittenbury said sales in the lead-up to Christmas were lower than in the past and he was unsure if trading on Boxing Day would help compensate.
"It will be a busy day.
Whether it makes a difference? People still only have the same amount of money to spend, don't they?" There will be extra bus and train services to and from the city and traders said city car parks would offer special deals for motorists.
Lord Mayor Stephen Yarwood said it would be great to see a vibrant city shopping precinct.
"There'll be plenty to see and do, not just shop.
It'll be great to see the city alive on Boxing Day," he said.