October 14, 2025, will mark a turning point for those working with import operations. On that day, the traditional Single Administrative Document (DUA), which for decades has been the standard for customs clearance, will cease to be used .
(REAF Advisory Note 46-25)
From that date, all declarations must be made using the new H1 system, a tool that is fully integrated into the framework of the Union Customs Code (UCC) and that completely transforms the way goods are declared at the border.
Although the news isn't new—it's been known since 2024 and many companies have had time to adapt—the change will now be permanent. And, as is often the case with reforms of this kind, the important thing isn't so much the technical innovation itself, but rather how it will affect the daily work of foreign trade departments, customs agents, and consultants.
From checkbox forms to email: a structural change
The old Single Administrative Document (SAD), with its numbered boxes and paper or PDF declarations, is becoming a thing of the past. It is being replaced by a fully electronic model, based on structured XML messages, which implies direct communication with the tax agency's systems and with the European customs network itself.
The new H1 system allows for automatic data validation, reuse of existing information from other platforms (such as enterprise ERPs or the Single Window for Customs), and minimizes errors previously caused by manual data entry or duplication. In practice, this translates to greater control, improved traceability, and a reduced margin of error. It also means that manual or partial procedures will become obsolete, forcing many companies to urgently review their IT systems and their connections with logistics providers.
A more demanding, but also safer format
From a technical point of view, the H1 is not just a change of format. It involves a complete reorganization of the information: the data is grouped into blocks, with different levels of detail depending on the type of regime (free circulation, customs warehousing, inward processing, etc.).
The Spanish Tax Agency (AEAT) has published tables and guides for columns H and I, specifying which fields are mandatory and which are optional in each case. Furthermore, the new structure clearly separates the roles of Importer, Declarant, Representative, and Consignee, providing the importer with their own field (including their EORI code or equivalent identification). This distinction, which was previously unclear, strengthens the traceability of transactions and allows for more precise control by the Tax Agency.
The system also aligns with other European frameworks, such as AES (exports), NCTS (transit), and ICS2 (entry security controls). Taken together, all of this points toward a 100% digital, interconnected, and data-driven customs system.
Solutions for complex cases: combinations of regimes
One of the issues that has generated the most confusion among operators is the management of combinations of customs procedures. Under the Precau system, it was possible to declare, for example, a combination of 40+44 or 40+51 in the same Single Administrative Document (SAD). With the Union Customs Code (UCC) system, this is no longer feasible for technical reasons, although the Spanish Tax Agency has offered a practical solution: from September 23, 2025, code 9001 can be used in the Supporting Documents to perform a "special date."
This allows the same item to be declared in multiple import declarations until the available gross weight is exhausted, avoiding the "uncancelled packages" errors that caused so much trouble for declarants. This is no small detail: this measure demonstrates that the new system, although more rigid, is beginning to adapt to the day-to-day operational realities.
Technological adaptation and internal review: what companies should do
From October 13th, the DUA system will no longer accept new import declarations. From the following day, only the H1 format will be accepted, in accordance with Annex B of Regulations (EU) 2015/2446 and 2015/2447. This means that companies must be prepared, with their systems aligned with the EUCDM (European Union Customs Data Model) validations and their teams trained to operate in the new environment.
It is advisable to review the following aspects before making the change:
- Internal processes: verify who is acting as the importer and whether the powers of representation (direct or indirect) are correctly updated.
- Technology integration: verify that the ERP or TMS is configured to generate and send compatible XML messages.
- Data matrices: identify which H/I column applies to each import flow (free practice, temporary, simplified, etc.) and which codes or documents are required.
- Staff training: it's not enough to just read the guide; you need to practice. Practice runs with the customs representative before the DUA (Single Administrative Document) is finalized will be crucial.
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A Àmbit Assessor, SL has 40 years dedicated to the tax, comptable and labor consultancy of the Pime.
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