Consumers travelling between Ireland and the UK will be able to avail of cut-price alcohol, cigarettes and perfume in the event of a no- deal Brexit.
The price of a packet of 20 cigarettes will be as little as €3 for people travelling from the UK into this country while spirits will also be dramatically cheaper.
However, the rare upside to Brexit for shoppers will come at a major cost to the Exchequer and retailers.
The return of duty-free shopping for people flying or sailing to the UK will reduce the Government's coffers by around €350m a year even before the related economic impact on the retail sector is taken into account.
The Dáil had passed legislation to continue restrictions on duty-free sales after the UK leaves the EU - but a decision in London means it will not now be implemented.
The UK chancellor revealed that he intends to reintroduce duty-free shopping for passengers travelling to EU countries if the UK leaves the EU without a deal on October 31.
As a result, Ireland will not put in place facilities to collect taxes for the UK.
It could mark the return of the so-called 'booze cruise' where day-trippers take the boat to the UK in order to stock up on cheap alcohol and cigarettes.
Duty-free shopping will not apply to passenger travel on the island of Ireland, between north and south.
Finance Minister Paschal Donohoe confirmed that in the event of no deal, the UK will assume the status of a 'third country' in terms of its trading relationship with the EU.
In a statement, Mr Donohoe said: "The effect of the announcement by the UK government today on the return of duty-free shopping between the UK and EU member states means that Ireland in respecting our international obligations will, as intended, reciprocate the UK government's decision and facilitate duty-free purchases for passengers travelling from Ireland to UK ports and airports.
"Passengers to Ireland purchasing duty-free goods in the UK must adhere to the personal consumption limits set out in EU law."
While the Irish Government is reluctantly allowing the return of duty-free, the UK is using it to show consumers what it sees as the upside of Brexit.
"As we prepare to leave the EU, I'm pleased to be able to back British travellers," Chancellor Sajid Javid said.
"We want people to enjoy their hard-earned holidays and this decision will help holidaymakers' cash go that little bit further."
Latest figures show that 7.6 million passengers arrived in Ireland from the UK in 2017.