What exactly is MIDA?
MIDA (ΜΙΔΑ) is AADE's new unified platform for collecting and managing data on real estate ownership, use and rental status, introduced as part of Law 5313/2026, published in Government Gazette A' 102 on 25 June 2026 (regfollower.com). It sits alongside the existing E9 property tax declaration and the Hellenic Cadastre, but its job is to cross-reference the two and flag mismatches automatically rather than wait for an audit.
From January 2026, AADE began matching E9 filings against Cadastral survey data, and owners have started receiving notifications asking them to confirm or correct their recorded details (design-construction.gr). The full registry, built with the Hellenic Cadastre, integrates legal, planning, forestry, tax and energy data into one profile per property. The rollout is phased: agricultural land came first, ahead of the October subsidy payment cycle, with an 8 to 10 month correction window for that category (athens-times.com). Residential and business property follows on its own declaration and correction timeline.
Why would my E9 be wrong in the first place?
Two common reasons. Either the declared square metres on your E9 have never matched the actual built area on the ground, sometimes because of a conversion, an extension, or an old semi-outdoor space now enclosed, or the declared use of the property (primary residence, rented, vacant, business) is out of date. Cross-checking against Cadastral records is now automatic, so gaps that sat quietly for years become visible immediately.
This matters more for foreign owners than it sounds. A flat bought years ago through an agent, or inherited without a full survey, can easily carry an E9 area that understates the real footprint. MIDA is what finally tests that figure against the Cadastre.
Can I fix an understated E9 area without a penalty?
Yes, but only during the current grace period. If the actual area of your property exceeds what is declared on your E9, you can declare the correct square metres through MIDA without a fine and without AADE recalculating ENFIA for the previous five years (en.rua.gr). POMIDA, the national federation of Greek property owners, has specifically welcomed this grace period as one of the most important parts of the reform (athens-times.com).
There is a further practical detail worth knowing: to increase your declared area, you do not need a full Electronic Building Passport in place first. Your declaration through MIDA has the legal force of a responsible statement (υπεύθυνη δήλωση), according to POMIDA's explanation of the mechanism (en.rua.gr). That lowers the barrier for owners who have been putting off a formal survey.
The catch is timing on the tax side, not the filing side. The extra area you declare now escapes retroactive ENFIA, but it starts being taxed as of 2027 (en.rua.gr). This is a one-off amnesty on the past, not a permanent exemption on the difference going forward.
What are the actual deadlines, and what do they cover?
| Requirement | Deadline | Penalty for missing it |
|---|---|---|
| Correcting an understated E9 area (grace period) | Ongoing during the current window, before general enforcement begins | None, if filed in time. No retroactive ENFIA on the corrected area |
| Declaring property use (residence, rented, vacant, business) | Standard filing deadlines under MIDA rules | 500 euros, from 1 November 2026 |
| Declaring a new lease or free concession of use | Within 3 months of the lease or concession starting | 500 euros standard fine |
| Updating land or building data linked to agricultural subsidy applications | Within 2 months of the start of the official application period | 500 euros standard fine |
| Intentionally false declaration used to obtain a state subsidy or grant | N/A | 1,000 euros |
The core enforcement date to hold in mind is 1 November 2026. Before that, correcting your figures is largely penalty-free. After it, a missing or late declaration of property use carries the standard 500 euro fine, and this provision is written directly into Law 5313/2026 (athens-times.com).
What must I declare about how the property is used?
Under MIDA, owners must state the specific use of each property: whether it is a primary or secondary residence, and whether it is under a long-term lease, a short-term (Airbnb-style) let, a financial leasing arrangement, or occupied free of charge by a family member or third party (zeya.com). This is a materially wider disclosure than the old E9, which mostly tracked ownership and broad category rather than actual use.
If your flat's status has changed since you last filed, say it moved from vacant to long-term let, or from your own residence to a family member living there rent-free, that change now needs to be reflected in MIDA within the applicable window. Owners who already run a compliant long-term let and have declared the lease to AADE, as covered in How to Find Tenants in Athens, should have most of this data ready. The new step is confirming it matches on the MIDA side too.
Does MIDA apply to me if I live abroad or hold the property through a Golden Visa?
Yes, without exception. Foreign nationals who own Greek property, whether bought outright, acquired through the Golden Visa programme, or received by inheritance, carry the same registration and declaration obligations as Greek residents. Managing the property from a distance does not reduce those obligations, and the system makes no distinction between resident and non-resident owners (design-construction.gr).
In practice this means the paperwork burden falls hardest on owners who are not in Greece to receive the AADE notification, read it in Greek, and act inside the window. If you hold property through the Golden Visa route, the letting restrictions and tax basics are covered separately in the Greece Golden Visa material, but MIDA compliance sits on top of those, as a distinct administrative obligation tied to the property itself rather than to the residence permit.
What should I actually check right now?
Four things, in order.
First, pull your current E9 and compare the declared square metres against any survey, floor plan or Cadastral extract you hold. If there is a gap, this is the moment to correct it under the penalty-free window.
Second, confirm the declared use matches reality: residence, long-term let, vacant, or business. If your flat is let and the lease was properly declared to AADE as described in Rent Collection in Greece, check that the MIDA-side use declaration reflects the same lease.
Third, if you have granted a family member free use of a property, or set up a lease, note the date it started. You have three months from that date to file, not three months from when you remember to.
Fourth, if any of your land is linked to an agricultural subsidy application, treat the shorter two-month window as the priority, since it moves first in the phased rollout.
What to do next
Pull your current E9, compare the declared area against any survey or Cadastral record you have, and file a correction now if there is a gap, while the grace period still applies. Check that your declared use, residence, long-term let, vacant, or free concession, matches reality, and note the three-month filing clock on any lease or concession. If you manage the property from abroad and want the MIDA cross-check, E9 correction and use declaration handled properly rather than risking the November deadline, mamaXO can review your filings as part of ongoing management and flag exposure before AADE does. For an assessment of your property's MIDA status, get in touch.
About mamaXO
mamaXO is an Athens-based property and Golden Visa operator. This guide is produced by the mamaXO editorial team and reviewed by our in-house legal, tax and property specialists.
