MRN in EU Customs: Origin and Structure

Trade Documents 24 Sept 2026 9 min read

Quick answer

An MRN (Master Reference Number) is a unique identifier assigned by EU customs authorities to customs declarations and related documents. It is essential for tracking and managing customs procedures within the EU single market.

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Key takeaways

The MRN is a unique registration number assigned by customs authorities to declarations, notifications, and proofs of customs status within the EU ^[1].
It follows a standardized structure including year, country code, unique identifier, procedure code, and a check digit ^[2].
MRNs are issued upon acceptance of customs declarations and are used for various customs procedures including import, export, transit, and proof of Union goods status ^[3].
MRNs can be communicated via electronic means or alternative formats such as bar codes or transit documents, depending on the procedure .
They are crucial for linking previous documents and declarations, such as temporary storage or entry summary declarations, to ongoing customs procedures .

What is an MRN and Why Does it Matter?

The Master Reference Number (MRN) is a registration number allocated by the competent customs authority to customs declarations, notifications, TIR operations, and proofs of the customs status of Union goods within the EU customs territory ^[1:1]. It serves as a unique identifier that enables customs authorities and economic operators to track and manage customs procedures efficiently.

For an EU-based business, the MRN number is fundamental because it confirms the acceptance of a customs declaration and provides a reference for all subsequent communications and controls related to that declaration. Without the MRN, it would be challenging to verify the status of goods in customs procedures or to link related customs documents.

The MRN is issued by the customs authority upon formal acceptance of a customs declaration, except in specific cases such as oral declarations or declarations recorded in the declarant’s records ^[3:1]. This means that once a customs declaration is lodged electronically or in another accepted form, the declarant receives the MRN number as confirmation.

In practice, the MRN number is used by importers, exporters, customs brokers, and other stakeholders to reference the customs declaration in all related processes, including transit, storage, and proof of Union goods status. This ensures traceability and compliance with EU customs law.

The Structure of an EU Customs MRN

The MRN number has a standardized format that facilitates its recognition and validation across all EU Member States. According to Commission Implementing Regulation (EU) 2015/2447, the MRN consists of five fields:

The last two digits of the year of formal acceptance of the declaration (YY) – two numeric characters.
The country code where the declaration or notification is lodged – two alphabetical characters (ISO alpha-2 code).
A unique identifier for the message per year and country – up to twelve alphanumeric characters.
A procedure identifier – a single alphabetical character indicating the customs procedure type.
A check digit – a single alphanumeric character used to verify the MRN’s validity ^[2:1].

For example, an MRN might look like this: 26FR1234567890B5, where “26” is the year, “FR” the country code (France), “1234567890” the unique identifier, “B” the procedure code, and “5” the check digit.

The procedure identifier is particularly important as it indicates the type of customs operation the MRN relates to. Some common procedure codes include:

A: Export only
B: Export and exit summary declaration
C: Exit summary declaration only
J: Transit declaration only
R: Import declaration only
S: Import declaration and entry summary declaration

This coding allows customs authorities and economic operators to quickly identify the nature of the procedure linked to the MRN ^[2:2].

When is an MRN Issued?

An MRN is issued by the customs authorities upon acceptance of a customs declaration, which can be lodged electronically or by other means, except in cases of oral declarations or declarations recorded in the declarant’s records ^[3:2]. The issuance of the MRN confirms that the declaration has been formally accepted and registered in the customs system.

The MRN is provided to the declarant along with the date of acceptance. This notification enables the declarant to reference the MRN in all subsequent communications with customs and other relevant parties.

It is important to note that the MRN is not issued before acceptance of the declaration. Therefore, businesses should ensure that their customs declarations are complete and accurate to avoid delays in obtaining the MRN number.

For transit operations and TIR procedures, the MRN is also issued upon acceptance of the transit declaration or TIR operation, serving as a reference throughout the transit process ^[4].

MRN for Different Customs Procedures

The MRN number applies to a wide range of customs procedures within the EU. These include:

Import Declarations: The MRN is assigned when goods enter the customs territory of the Union and a declaration is accepted by customs authorities ^[2:3].
Export Declarations: When goods leave the EU customs territory, an MRN is issued upon acceptance of the export declaration ^[2:4].
Transit Declarations: For goods in transit through the EU, the MRN is issued upon acceptance of the transit declaration and is used to track the movement until exit ^[4:1].
Exit Summary Declarations: The MRN is assigned for exit summary declarations, which provide customs with advance information on goods leaving the EU ^[2:5].
Proofs of Customs Status of Union Goods: Customs goods manifests and other proofs confirming the Union goods status are attributed an MRN to ensure traceability ^[5].

Depending on the procedure, the MRN number may be linked to other customs documents or declarations, such as entry summary declarations or temporary storage declarations, to provide a comprehensive reference system within the customs clearance process ^[6].

Using MRNs for Previous Documents and Temporary Storage

In many customs procedures, referencing previous documents is mandatory to establish continuity and legal compliance. The MRN number plays a crucial role here as the standard reference for these previous documents.

For example, when goods are moved under temporary storage, the MRN of the temporary storage declaration must be entered in subsequent declarations related to those goods. If the temporary storage declaration does not cover all items of goods, the relevant item numbers must also be provided to ensure unambiguous identification ^[7].

Similarly, when lodging transit declarations, the MRN of the previous customs procedure or document must be referenced to link the current procedure with the prior one. This includes referencing customs declarations for release for free circulation or entry summary declarations where applicable ^[6:1].

This system ensures that customs authorities can trace the history of goods through their various customs procedures, facilitating risk analysis, compliance checks, and enforcement actions.

Alternative Means of Communicating an MRN

While electronic data-processing techniques are the primary means of communicating MRNs to customs authorities, alternative methods are permitted depending on the customs procedure and national practices.

For transit declarations and TIR operations, the MRN may be submitted by means such as:

Bar codes
Transit accompanying documents
Transit/security accompanying documents
TIR carnets (for TIR operations)
Other means allowed by the receiving customs authority ^[4:2].

For proofs of the customs status of Union goods, such as T2L or T2LF documents and customs goods manifests, the MRN can also be communicated via bar codes, status registration documents, or other means permitted by the customs authority ^[8].

These alternative communication methods provide flexibility for economic operators and customs authorities, especially where electronic systems may not be fully accessible or for paper-based procedures.

MRN for Proof of Union Goods Status

The MRN number is also assigned to customs goods manifests that serve as proof of the customs status of Union goods. Such manifests are attributed one MRN each and must cover goods loaded in a Union port that have the customs status of Union goods ^[5:1].

This MRN facilitates the verification and control of goods within the EU customs territory, especially for goods in transit or under customs control. Customs authorities may accept commercial, port, or transport information systems for submitting requests for endorsement and registration of the customs goods manifest, provided all required information is included ^[5:2].

For travellers who are not economic operators, requests for proof of customs status of Union goods may be made on paper, and the MRN can be communicated through documents other than electronic data-processing techniques ^[8:1].

FAQ

Where can I find my MRN number?
The MRN number is provided by the customs authority upon acceptance of your customs declaration. It is typically found on the customs declaration acceptance notification or related customs documents issued by the authority.

How do I find my MRN number in the UK?
Although the UK is no longer part of the EU customs territory, the term MRN number may still be used in UK customs procedures. The MRN is issued by UK customs authorities upon acceptance of declarations and can be found on the customs declaration paperwork or electronic notification.

What is MRN UK?
MRN UK refers to the Master Reference Number issued by UK customs authorities for customs declarations and related documents. It serves the same purpose as the EU MRN number but applies within the UK customs regime.

What is the MRN number in NHS?
The MRN in the NHS context stands for Medical Record Number, which is unrelated to customs procedures. It is a unique identifier used within the National Health Service for patient records and should not be confused with the customs MRN number.

Next steps

Confirm the MRN number format used by your national customs authority for your specific customs procedure.
Ensure your customs declarations include all required data elements to obtain the MRN upon acceptance.
Reference the correct MRN number in all subsequent customs documents and communications to maintain traceability.
Verify the procedure identifier within the MRN to confirm it corresponds to your customs operation.
Use alternative means of MRN communication, such as bar codes or transit documents, if electronic submission is not feasible.

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