UDI obligations under Regulation (EU) 2017/745 do not all apply on the same day. MDR Article 123 phases the UDI carrier obligations on labels and packaging by risk class: implantable and Class III devices from 26 May 2021, Class IIa and IIb from 26 May 2023, and Class I from 26 May 2025. Direct marking of reusable devices that require reprocessing follows two years after each labelling date. The UDI system itself under Article 27, the Annex VI Part B database submission under Article 29, and the interaction with Article 34 on the functionality of EUDAMED modules are separate obligations with their own timing. Regulation (EU) 2023/607 extended certain MDD/AIMDD legacy-certificate transitional windows but did not reset the Article 123 UDI carrier dates. For a new device placed on the EU market in 2026, every class-specific UDI carrier date is already in force, and full UDI compliance is expected from the outset.

By Tibor Zechmeister and Felix Lenhard. Last updated 10 April 2026.

TL;DR

  • MDR Article 123 phases the UDI carrier obligations by risk class, starting 26 May 2021 for implantable and Class III, 26 May 2023 for Class IIa and IIb, and 26 May 2025 for Class I.
  • Direct marking of reusable devices that require reprocessing is staged two years after each class's label date: 26 May 2023 for implantable and Class III, 26 May 2025 for IIa and IIb, 26 May 2027 for Class I.
  • The UDI system itself under Article 27 and the device registration obligation under Article 29 apply as of the MDR date of application. The class-staged dates in Article 123 apply to the carrier obligation on the label and packaging, not to the existence of the UDI system.
  • Regulation (EU) 2023/607 extended the validity of certain MDD/AIMDD certificates and the sell-off provisions for legacy devices. It did not change the Article 123 UDI carrier dates for new MDR devices.
  • As of April 2026, every class-specific UDI label date is in force. A new device entering the EU market today plans for full UDI compliance — carrier, direct marking where applicable, and Annex VI Part B submission — from day one.

The Article 123 phasing scheme

MDR Article 123 is the transitional provisions article of Regulation (EU) 2017/745. Most founders know it as the article that was extensively amended by Regulation (EU) 2023/607 to extend legacy MDD and AIMDD certificate validity. That amendment is real and important, but it is not the part of Article 123 that governs UDI timelines for new MDR devices. The UDI phasing sits in its own paragraphs of Article 123 and operates on a different logic.

The phasing logic is risk-based. Higher-risk devices have to carry the UDI on the label first, and lower-risk classes follow in two-year steps. The reasoning is straightforward: implantable and Class III devices have the highest traceability stakes, so the carrier obligation hits them first, while Class I devices — much larger in number and run by much smaller organisations — are given more time to adapt packaging, printing, and ERP systems.

Two principles are worth stating before the dates themselves. First, the class-staged dates in Article 123 apply specifically to the obligation that the UDI carrier (barcode, DataMatrix, or other AIDC technology specified in Annex VI Part C) must be placed on the label of the device and on higher levels of packaging. They do not delay the existence of the UDI system under Article 27, and they do not delay the device registration obligation under Article 29. Second, the direct marking obligation for reusable devices under Article 27(4) is a separate, additional obligation with its own two-year offset from the labelling date for the same class.

The by-class deadlines

The concrete dates set out in MDR Article 123 for UDI carrier obligations on the label and higher levels of packaging are as follows.

Implantable devices and Class III devices. The UDI carrier must appear on the label of the device and on all higher levels of packaging from 26 May 2021 — the MDR date of application. There is no phase-in window for this class. From day one of the MDR, the carrier obligation applied.

Class IIa and Class IIb devices. The UDI carrier obligation applied from 26 May 2023, two years after the implantable and Class III date. Between 26 May 2021 and 26 May 2023, Class IIa and IIb devices placed on the market under MDR were expected to be progressing toward UDI carrier compliance but were not yet legally required to carry it on the label.

Class I devices. The UDI carrier obligation applied from 26 May 2025, two years after the Class IIa and IIb date. For Class I devices, the phase-in window was four years from the MDR date of application.

As of April 2026, every one of these dates is in the past. Every device class — implantable, III, IIb, IIa, and I — is subject to the UDI carrier obligation on the label and packaging. There is no class remaining in a pre-carrier state.

Label obligations versus database obligations — different deadlines

A point of frequent confusion is that the Article 123 staged dates apply to the physical label carrier obligation under Article 27, not to the Annex VI Part B database submission obligation under Article 29. These are two separate deliverables with two different timing regimes.

The database submission under Article 29(1) is required before placing a device on the market, and it has always been so under the MDR. There is no two-year, four-year, or class-staged phase-in for submitting the Annex VI Part B data elements to the UDI database. The only thing that has modulated the database obligation in practice is the functionality status of the relevant EUDAMED modules under Article 34 — the mandatory use of EUDAMED modules is conditioned on the Commission declaring the module functional, and the UDI and device registration module has followed its own functionality timeline, separate from Article 123.

The practical consequence is that a Class I manufacturer in, say, 2024 faced two different timing questions at once. The label carrier obligation was not yet in force (it arrived 26 May 2025). But the Article 29 database submission obligation was in force the moment the device was placed on the market, subject to the Article 34 functionality status of the UDI module. Conflating the two led some teams to assume they had until 2025 for everything, when in fact the database work and the labelling work were on different clocks.

The legacy device situation

For devices that had already been on the market under the MDD or AIMDD and migrated to MDR under the transitional provisions, the situation is different again. Regulation (EU) 2023/607 is the piece of law that matters here.

Regulation (EU) 2023/607 of 15 March 2023 amended Regulation (EU) 2017/745 to extend the validity of certain MDD and AIMDD certificates and the sell-off provisions for devices lawfully placed on the market before the MDR date of application. The extensions are conditional on a set of requirements — including, among others, that the manufacturer has a compliant quality management system and has lodged a formal application with a notified body by specified dates. The purpose of (EU) 2023/607 was to prevent a supply crisis for established devices whose MDR certification had been delayed by notified body capacity constraints.

What (EU) 2023/607 did not do was change the Article 123 UDI carrier dates for devices placed on the market under MDR. A new MDR device entering the market in 2023, 2024, 2025, or 2026 has always been subject to the Article 123 class-staged carrier dates in their original form. The legacy extensions in (EU) 2023/607 operate on a different axis — certificate validity and sell-off windows — not on the UDI carrier phasing. For founders, the clean reading is: if your device is a new MDR device, (EU) 2023/607 does not relax your UDI carrier obligation at all.

What is in force in 2026

As of April 2026, the complete set of UDI carrier and direct marking deadlines in Article 123 is already in force for every class of new MDR device. The full picture for a founder starting a certification project today is this.

  • The UDI system under Article 27 applies to every device on the EU market other than custom-made and investigational devices. This has been in force since 26 May 2021.
  • The UDI carrier on the label and higher packaging levels is required for every class: implantable, III, IIb, IIa, and I. Every class-staged date (2021, 2023, 2025) has passed.
  • The direct marking obligation under Article 27(4) for reusable devices that require reprocessing is in force for implantable and Class III (from 26 May 2023) and for Class IIa and IIb (from 26 May 2025).
  • The device registration obligation under Article 29 — the Annex VI Part B submission — applies before placing a device on the market, subject to the Article 34 functionality status of the EUDAMED UDI and device registration module.
  • Regulation (EU) 2023/607 legacy extensions remain relevant for MDD and AIMDD certificates and sell-off, but do not modify the UDI carrier dates for new MDR devices.

For a new device entering the market today, the regulatory position is the simplest it has been since 2021: full UDI compliance applies, no phase-in windows remain to plan around for the label carrier, and the design-time decision is whether to execute all of it cleanly at first market placement or to discover the gaps later under audit.

What is still upcoming

The one UDI timeline item that is still upcoming as of April 2026 is the direct marking obligation for reusable Class I devices that require reprocessing. Under Article 123, direct marking follows two years after the label date for each class. Class I label obligation applied from 26 May 2025, so Class I direct marking for reusable devices requiring reprocessing applies from 26 May 2027.

A founder bringing a reusable Class I device — a reusable surgical instrument, for example — to market today should plan for direct marking at the design stage rather than retrofitting it in 2027. Direct marking touches the device itself (engraving, laser marking, or other permanent identification technology), not just the label, and the engineering effort to add it after the device is finalised is meaningfully larger than building it in from the start.

Beyond that, the remaining uncertainty in the UDI timeline is not in Article 123 at all but in Article 34 — the status of EUDAMED module functionality. The mandatory use of the UDI and device registration module is conditioned on the Commission declaring the module functional, and founders should check the current EUDAMED module status rather than assume a specific mandatory-use date. That status changes independently of the Article 123 phasing.

Common founder mistakes on the UDI timeline

"Regulation (EU) 2023/607 gives us more time on UDI." It does not. (EU) 2023/607 extended MDD and AIMDD legacy certificate validity. It did not touch the Article 123 UDI carrier phasing dates for new MDR devices. A founder who reads "2023/607 extended MDR transitional periods" as "UDI is delayed" is making a consequential category error.

"Class I devices are exempt until EUDAMED is fully mandatory." The Article 123 Class I label carrier date (26 May 2025) is independent of the EUDAMED module functionality status. The label obligation is a product-and-packaging obligation, not a database obligation, and it is in force today for Class I.

"The database deadline and the label deadline are the same." They are not. Article 29 database submission applies before placing the device on the market, subject to Article 34 functionality. The Article 123 class-staged dates apply to the label and packaging carrier. Two different deliverables, two different clocks.

"Direct marking and label marking are the same obligation." They are not. Direct marking under Article 27(4) applies to reusable devices that require reprocessing, is on the device itself (not just the label), and follows the label date by two years for the same class.

"We will add the UDI to the label after certification." The label is part of the technical documentation assessed during conformity assessment. Adding the UDI after certification is a design change that touches the file and the certificate. Build it in from the start.

The Subtract to Ship angle on UDI timelines

The Subtract to Ship framework for MDR applied to UDI timelines produces a short answer. For any new device entering the EU market in 2026, there is no class-based phase-in to plan around for the label carrier. Every date in Article 123 for the UDI label obligation is in force. Every activity that consists of "tracking whether our class's UDI date has arrived yet" is waste, because the answer is yes for every class. The only live timing question that remains is direct marking for reusable Class I devices (2027) and the Article 34 EUDAMED module functionality status for database submission.

The real work is narrow and concrete. Build the UDI-DI and UDI-PI into the label at design time. Build direct marking into any reusable device at design time, regardless of class. Submit the Annex VI Part B data under Article 29 before placing the device on the market, subject to module functionality. Stop reading (EU) 2023/607 as if it relaxed the carrier dates — it did not. Everything outside these activities is a candidate for removal.

Reality Check — Where do you stand on UDI timelines?

  1. Do you know the risk class of your device and can you state the Article 123 UDI label date that applied to that class?
  2. If your device is a reusable device requiring reprocessing, have you built direct marking into the design, or are you planning to retrofit it?
  3. Do you understand that Regulation (EU) 2023/607 does not extend the UDI carrier dates for new MDR devices?
  4. Do you have the label design with the machine-readable and human-readable UDI carrier ready for Notified Body assessment?
  5. Have you separated the label obligation (Article 27, staged by Article 123) from the database obligation (Article 29, subject to Article 34 functionality) in your plan?
  6. For a reusable Class I device, have you planned for the 26 May 2027 direct marking obligation?
  7. When was the last time you checked the current EUDAMED UDI and device registration module functionality status?

If you cannot answer five or more of these cleanly, the UDI timeline is not yet a solved workstream.

Frequently Asked Questions

When did UDI obligations start under MDR? The UDI system under Article 27 applied from the MDR date of application, 26 May 2021. The class-staged carrier obligations under Article 123 started on the same day for implantable and Class III devices, 26 May 2023 for Class IIa and IIb, and 26 May 2025 for Class I.

What is the UDI label deadline for Class I devices? Class I devices had to carry the UDI on the label and on higher levels of packaging from 26 May 2025 under MDR Article 123. That deadline is in force today.

When does direct marking apply? Direct marking under Article 27(4) applies to reusable devices that require reprocessing, two years after the label date for each class. So from 26 May 2023 for implantable and Class III, from 26 May 2025 for Class IIa and IIb, and from 26 May 2027 for Class I.

Did Regulation (EU) 2023/607 extend the UDI deadlines? No. Regulation (EU) 2023/607 extended the validity of certain MDD and AIMDD legacy certificates and the sell-off provisions for legacy devices. It did not change the Article 123 UDI carrier phasing dates for new MDR devices.

Is the UDI database submission on the same timeline as the label carrier? No. The label carrier obligation is staged by class under Article 123. The Annex VI Part B database submission obligation under Article 29 applies before placing the device on the market, subject to the Article 34 functionality status of the EUDAMED UDI and device registration module. They are two separate timelines.

What is still upcoming in the UDI timeline as of 2026? The main remaining class-staged date is 26 May 2027 for direct marking of reusable Class I devices that require reprocessing. Everything else in the Article 123 phasing is already in force.

What governs the detailed functioning of the UDI database? Commission Implementing Regulation (EU) 2021/2078 of 26 November 2021 lays down the rules for the application of Regulation (EU) 2017/745 as regards the European Database on Medical Devices, including the UDI database module.

Sources

  1. Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices, Article 27 (Unique Device Identification system), Article 29 (registration of devices), Article 34 (functionality of Eudamed), Article 123 (entry into force and date of application, including the UDI class-staged dates), Annex VI Part C (the UDI system). Official Journal L 117, 5.5.2017.
  2. Regulation (EU) 2023/607 of the European Parliament and of the Council of 15 March 2023 amending Regulations (EU) 2017/745 and (EU) 2017/746 as regards the transitional provisions for certain medical devices and in vitro diagnostic medical devices. OJ L 80, 20.3.2023.
  3. Commission Implementing Regulation (EU) 2021/2078 of 26 November 2021 laying down rules for the application of Regulation (EU) 2017/745 of the European Parliament and of the Council as regards the European Database on Medical Devices (Eudamed). OJ L 426, 29.11.2021.

This post is part of the EUDAMED, UDI and Registration category in the Subtract to Ship: MDR blog. Authored by Felix Lenhard and Tibor Zechmeister. The pillar post for this cluster is What is EUDAMED?. For founders building a new device today, the clean reading of Article 123 is that every UDI label deadline is already in force — the planning question is execution quality, not phase-in strategy.