In the next ten days, the way the marketplace works in payments is changing. From December 1, all retailers, from small shops to large chains, will be required to accept mandatory payments via IRIS and have POS, cash, and APA connected in the same environment. For consumers, this means easier and more direct transactions. For professionals, however, a new reality begins with strict rules, constant cross-checking, and significant adjustment costs.

Despite high public use of IRIS – over 4.1 million consumers and 571,000 professionals – the market remains cautious. Last month’s technical problems created delays and the need for an extension, at a time when many small and medium-sized businesses have not had time to complete upgrades. The ADC has completed the new Instant Payments framework and now sets a clear rule: every payment, whether by card or IRIS, must go through the cash system and a receipt must be issued in real time.

The crucial thing for professionals is what will happen from 1 December and how strictly the penalties will be applied. The finance ministry and the AADE assure that there will be a transitional period of recommendations rather than immediate fines, especially when technical problems are identified that are not the fault of businesses. Nevertheless, the fear of the market is that if the POS – cash register – Taxisnet interfaces do not work flawlessly, false readings and unfair charges may occur.

But the new framework provides for high penalties for those who do not adapt. A fine of 10,000 euros for companies with simple books and 20,000 euros for double-entry books if they do not accept IRIS or have not completed the interface correctly. In settlements up to 500 inhabitants and on islands below 3,100 inhabitants, the fine is halved. At the same time, fines of 100,000 to 300,000 euros are foreseen for companies managing POS, while even the failure to upgrade a single terminal will result in a fine of 500 euros per device.

The cost of adaptation is also a key issue for SMEs. A business can incur up to 1,500 euros for POS and cash register upgrades alone, while the total cost of digital migration is estimated at 6,000 to 8,000 euros per year for a small or medium business, professional bodies point out.
Electronic payments, however, are well established in everyday life. Bank of Greece data show that active cards reach 21.6 million, while the average transaction value falls to 43 euros, an indication that consumers are using cards and IRIS even for small amounts. From mid-2026, IRIS will be extended to Italy, Spain, Portugal, Scandinavia, and Poland via EuroPA, allowing direct money transfers outside Greece.