The short answer: the correction reform starts on 1 July 2028
If your business files through OSS (the One Stop Shop, the EU's single VAT return for cross-border consumer sales) or IOSS (the Import One Stop Shop for low-value imported goods), a new way to fix mistakes in past declarations is coming. It's not arriving in 2027, whatever some summaries say. It starts on 1 July 2028. The rule sits in Article 3 of Council Directive (EU) 2025/516, part of the VAT in the Digital Age package, known as ViDA. What actually changes on 1 January 2027 is a batch of minor technical adjustments for OSS/IOSS users, plus an extension of the scheme to certain distance sales in the energy sector. Neither of those touches how corrections work. Commission Implementing Regulation (EU) 2026/1869, adopted on 27 July 2026, confirms the same split: registration-data changes land in 2027, but the real correction reform only takes effect from July 2028.
How do OSS and IOSS corrections actually work today?
Right now, the rule is unforgiving. Once you've confirmed a return in your national e-filing portal (in Estonia, that's e-MTA), you can't touch it again, even if the official filing deadline hasn't passed yet. According to the Estonian Tax and Customs Board's guidance, any error you catch afterwards has to be corrected in a later period's return, although you still have to pay the amount you originally declared, mistake and all, until the fix goes through. in Latvia The State Revenue Service describes the identical model: a confirmed return cannot be deleted or edited, so any correction rides along on the next quarterly or monthly filing. If you're selling into several EU countries through OSS or IOSS from Estonia, Latvia or Lithuania, this is almost certainly the process you're already living with.
What does ViDA actually change?
From 1 July 2028, correcting a return becomes a two-track process instead of one. If you spot the mistake before the statutory filing deadline for that return has passed, you'll be allowed to amend the same declaration directly: the fix lands in the return you're still working on, not in some future one. This sits in Articles 365, 369g and 369t of the VAT Directive, covering the non-Union OSS scheme, the Union OSS scheme and IOSS, and the same logic will apply to the new scheme for transfers of own goods. If the error relates to an earlier period and you only find it after that deadline has already passed, nothing changes: the correction still gets carried into a later return, exactly as it does today.
The three-year window, what you'll need to report, and the filing calendar
When a correction does have to go into a later return, you'll need to specify the member state of consumption, the original tax period, and the exact amount being corrected. That right to correct runs for three years from the statutory deadline of the original return, not from whenever you actually filed it, which matters if you tend to file early. For context, OSS returns are currently quarterly and IOSS returns monthly, both due by the end of the month following the tax period. None of that filing rhythm changes under ViDA, only what you're allowed to do once a mistake turns up.
What happens to your correction rights if you leave OSS?
Here's the part sellers often miss. If your business has deregistered from the scheme, been excluded from it, or switched its member state of registration, you lose the ability to fix a later-discovered error through OSS or IOSS at all. The directive is explicit that in that situation you deal directly with the tax authority of the country of consumption instead: no more single portal, no more single point of contact. Estonian practice already works this way: before you deregister from the company register, you first have to close your special-scheme registration in e-MTA and file a final period return. After that, every further correction is a country-by-country conversation, not a single filing.
What should you actually change before July 2028?
Three things are worth locking in now, well ahead of the deadline. First, keep every OSS/IOSS return under internal review right up until its filing deadline, because after 2028 that window is exactly when a real, low-friction correction becomes possible. Miss it, and you're back to the multi-period process. Second, hold on to transaction-level records for longer than you might think you need to, since corrections can reach up to three years back. Third, start thinking through how refunds and top-up payments will actually flow once a fix can land in your current return instead of a future one. Your bookkeeping and cash-flow planning will need to reflect that. One more thing to flag: Implementing Regulation (EU) 2025/518 reworks the administrative side of OSS/IOSS, including Articles 61 and 61a, but exactly how the Estonian, Latvian and Lithuanian tax portals will display the new correction window has not been confirmed yet. Worth checking again as 2028 gets closer.
FAQ
When will the ViDA OSS correction rule go into effect?
The ViDA OSS correction rule will take effect from July 1, 2028, not 2027. Only minor clarifications for OSS/IOSS users will take effect on January 1, 2027.
How can the OSS/IOSS declaration be corrected now?
Currently, a confirmed OSS/IOSS declaration cannot be changed. The error must be corrected in the declaration for the next period, but the amount originally declared must still be paid.
What will change with the ViDA correction rules from 2028?
From 1 July 2028, if an error is discovered before the submission deadline, the same declaration can be amended. If the error is discovered after the deadline, the correction will still be applied to a later declaration.
How long is the right to rectification valid under the new ViDA rule?
The right of rectification is valid for three years from the mandatory filing date of the original return, not from the actual filing date.