When a company temporarily posts workers to another EU country, one of the first issues it must determine is which social security system will continue to apply. In many cases, this is evidenced by the A1 certificate, which shows that the worker remains subject to the social security system of the home country.
The European Union now intends to change the way this certificate is managed. On 15 September 2026, the European Commission presented the European Social Security Pass (ESSPASS), a system designed to digitalise the application, issuance and verification of European social security documents. The A1 certificate for posted workers is one of the documents concerned.
This guide explains what will change with the digital A1 certificate, when the new system could start to apply and, above all, what companies posting workers across Europe currently need to do.
What is the A1 certificate and when does a company need it?
The A1 certificate, also known as the A1 form, confirms which social security legislation applies to a person in a cross-border situation. Where the conditions for a posting are met, it shows that the worker remains subject to the social security system of the home country during that period.
💡 For example, if a Spanish company sends an employee to Belgium for several months, the worker may remain subject to Spanish social security. In that case, the A1 certificate proves to the Belgian authorities that the worker continues to pay social security contributions in Spain during the posting.
The legal framework is mainly set out in Regulations (EC) No 883/2004 and 987/2009. EU coordination is based on a basic principle: a person should be subject to the social security legislation of only one Member State. However, determining which Member State is competent requires an assessment of how, where and for whom the person works. Article 12 of Regulation 883/2004 covers certain temporary postings.
What is ESSPASS and how will it change the digital A1 certificate?
A European system for managing social security documents
ESSPASS is an EU initiative intended to make it easier to manage certain social security documents when a person works or moves between different Member States. The proposal is set out in COM(2026) 980 final – 2026/0271(COD) and aims to create a common system allowing documents such as the A1 certificate to be managed digitally and verified across countries. The aim is for these documents to be applied for, received, stored, presented and verified digitally through a common European system.
For companies, this could simplify the process. For example, if several workers are posted to another Member State and an inspection takes place, the authorities could more easily verify whether the A1 certificate is authentic, valid and corresponds to the worker and the declared period. The company will still need to provide correct information on who the worker is, which company employs them, where they will work, for how long and under what conditions. ESSPASS may simplify document management, but it does not replace the need for a proper assessment before the posting begins.
The A1 certificate will be one of the first documents to be digitalised
The European Commission plans to begin the implementation of ESSPASS with the A1 certificate for posted workers. According to the proposed timetable, this first phase would begin approximately one year after the ESSPASS Regulation enters into force. Other social security documents, such as the European Health Insurance Card, would be added later. The first phase specifically concerns the A1 certificate for posted workers. For other situations, such as people who habitually work in several Member States, the timetable and rules will need to be checked once the final legislation is adopted.
Will the paper A1 certificate disappear?
Not necessarily. The proposal does not mean that all paper certificates will immediately disappear. The Commission provides for the possibility of continuing to use secure paper formats during the implementation period. ESSPASS should also be distinguished from electronic systems that already exist today. In several EU countries, it is already possible to apply for or download an A1 certificate digitally, but this is not the same as ESSPASS.
💡 The main change would be the creation of a common European system, designed to make documents easier to use and verify when a worker moves from one country to another.
When will the digital A1 certificate enter into force?
There is not yet a final date for the new system to apply. The Commission’s proposal starts the legislative process, which must then be considered and approved by the European Parliament and the Council.
| Stage | Status or proposed timetable |
|---|---|
| Presentation of the Fair Labour Mobility Package | 15 September 2026 |
| Legislative procedure | Examination and negotiations by the European Parliament and the Council |
| Entry into force of ESSPASS | Will depend on the final text adopted and published |
| First phase: A1 for posted workers | One year after the Regulation enters into force |
| Other social security documents | Gradual inclusion within the announced three-year period |
Until the new rules are adopted and become applicable, companies must continue to use the national procedures currently in force.
A1, ESSPASS and posting declarations, what are the differences?
The A1 certificate, the future ESSPASS and national posting declarations serve different purposes. Each Member State may also impose its own administrative requirements before or during a temporary provision of services.
| Aspect | A1 certificate | ESSPASS | National posting declarations |
|---|---|---|---|
| What is it? | A document confirming which social security legislation applies to the worker | Future European system for digitally managing and verifying social security documents | Declarations required by individual Member States to notify certain postings of workers |
| What is its purpose? | To show in which country the worker remains insured | To facilitate the application, storage, presentation and digital verification of the A1 and other documents | To inform the authorities of the destination country of the worker’s temporary presence |
| Is it currently in force? | Yes | For now, it is a legislative proposal | Yes, according to the rules of each Member State |
| Who manages it? | The competent social security institution | The future ESSPASS system | The authority or platform designated by each Member State |
| Does it replace the others? | No | No. It does not remove the legal function of the A1 or national obligations | No. It does not replace the A1 |
| What should companies do today? | Apply for it where required | Follow the development of the reform | Check the formalities required in the country to which the worker is posted |
Is an A1 certificate enough to post a worker?
No. A company temporarily sending workers to another Member State must also check the labour and administrative obligations of the destination country. Many EU Member States require, for example, a prior posting declaration. The name of the declaration and the procedure vary from one country to another, and each State uses its own platforms and notification systems.
💡 In addition to the declaration, the company must check the employment conditions that have to be respected during the posting, including the applicable remuneration, working time, rest periods, holidays, health and safety requirements and certain conditions laid down in collective agreements.
Having an A1 certificate therefore does not mean that the company can simply continue applying all the conditions of the employment contract from the home country. Other obligations may also apply, such as appointing a contact person, keeping certain employment documents available, registering workers’ presence or providing additional information to the national authorities.
Obligations vary depending on the destination country
Although the posting of workers is based on common EU rules, their practical application depends to a significant extent on each Member State. Before starting an international assignment, the company should therefore check at least three points: which social security legislation applies and whether an A1 certificate is required; which posting declaration is required in the destination country; and which employment conditions and national formalities must be respected during the provision of services.
💡 For example, a Spanish company sending workers to Belgium may need an A1 certificate issued by the Spanish social security authorities while also having to submit a LIMOSA declaration in Belgium and comply with the applicable Belgian employment conditions. You can also consult our guide on posting workers to Belgium.
What should a company check before posting workers to another Member State?
Preparing the posting correctly
The digitalisation of the A1 does not change the fact that most problems should be anticipated before the worker starts providing services in another country. Before applying for the A1, the company should therefore identify the specific situation: who the employer is, where the worker will work, for how long and what activity will be carried out. A prior review should include at least the following points:
| Area to review | What the company should check |
|---|---|
| Type of mobility | Determine whether it is a temporary posting or habitual work in two or more Member States |
| Social security and A1 | Identify which social security legislation applies and apply for the A1 certificate where required |
| Declaration in the destination country | Check whether the destination country requires a prior posting declaration or another equivalent administrative formality |
| Employment conditions | Review remuneration, working time, rest periods, holidays and other mandatory employment conditions in the destination country |
| Sector-specific obligations | Check whether additional requirements apply because of the sector or activity |
| Permits and authorisations | Check whether work or residence permits, professional authorisations or recognition of qualifications are required |
| Posting documentation | Keep contracts, A1 certificates, declarations, payslips and other relevant documents in an accessible file |
| Monitoring the assignment | Monitor the dates and update the formalities if the duration, place of work, duties or other relevant aspects change |
Before sending staff to another Member State, the company should also review the labour and administrative obligations of the destination country and, where relevant, immigration and professional requirements. This also makes it easier to respond quickly if a labour or social security inspection takes place.
Obligations of the company in the destination country
Depending on the Member State, the client or host company may also have certain obligations concerning the verification, retention or communication of documents to the authorities.
💡 For this reason, where there is subcontracting or a cross-border provision of services, it is advisable to clarify who is responsible for each formality and who keeps the relevant supporting documents.
Where the posted worker is not an EU citizen, the analysis must be even more careful. Holding a residence or work permit in one Member State does not necessarily mean that the worker may work freely in every other EU country. The company must check the rules applicable in the destination country. You can also consult our analysis on the posting of third-country national workers within the European Union.
What happens if there is an inspection during the posting?
During an inspection, the authorities may check whether an A1 certificate exists, whether the relevant national declaration has been submitted and whether the documents correspond to the work the employee is actually carrying out.
💡 For this reason, the employment contract, payslips, place of work, duration of the assignment, identity of the employer and administrative declarations should be consistent.
If an authority requests documents, the company should first identify which workers and which period are being examined, which authority is carrying out the inspection and what information is being requested. Any differences should be analysed before responding.
💡 We advise companies on European labour mobility, posting of workers, social security, A1 certificates, national obligations and inspections relating to cross-border activities. An early review of the file can help identify risks before they lead to an administrative or employment issue.
What is the Fair Labour Mobility Package?
On 15 September 2026, the European Commission presented the Fair Labour Mobility Package, a package of measures concerning labour mobility. Its scope goes well beyond the A1 certificate. It includes the digitalisation of social security documents, portability of qualifications, recognition of professional qualifications and stronger cooperation between labour authorities.
A document issued in one country may be difficult to verify in another; recruitment may be delayed because a qualification has not yet been recognised; and an inspection may require information held by several different administrations. The European Commission aims to make these procedures more accessible and give authorities better tools to verify compliance.
| Proposal | Expected change | Main groups concerned |
|---|---|---|
| ESSPASS Regulation | Digital and verifiable social security documents | Companies, mobile workers and public authorities |
| Skills Portability Act | Digital format and tools for comparing qualifications | Employers and professionals |
| Reform of the European Labour Authority | More cooperation, risk analysis and inspections | National authorities and cross-border companies |
| Reform of Directive 2005/36/EC | Simplification of professional recognition | Professionals in regulated activities |
| Directive on qualifications of third-country nationals | Common rules to facilitate recognition | International professionals and recruiting companies |
For companies operating in several Member States, these reforms form part of a wider framework of European Union law and EU regulatory monitoring and compliance. The package is not a single piece of legislation. Each proposal will follow its own legislative procedure.
More cooperation under the reform of the European Labour Authority (ELA)
The proposed reform of the European Labour Authority (ELA) aims to provide more support to national authorities. Its objectives include improving cross-border cooperation, supporting inspections and making mediation in disputes between administrations more efficient. The proposal also seeks to extend ELA’s role in relation to abuses affecting third-country nationals and undeclared or illegal employment.
For companies, this may mean that authorities will have greater capacity to connect information coming from different Member States. This makes it even more important for contracts, actual activities, labour declarations and social security documentation to be consistent. ESSPASS and the ELA reform therefore operate in complementary areas: ESSPASS aims to facilitate the exchange and verification of information, while the reform of ELA seeks to strengthen cooperation between the authorities responsible for enforcement.
💡 Administrative simplification should not be confused with a reduction in compliance obligations.
Recognition of qualifications and recruitment of foreign professionals
The package also aims to make it easier for qualifications to be presented, compared and recognised between countries. For a company seeking to recruit specialised staff, this part of the reform may be just as relevant as the A1 certificate. However, three separate issues should be distinguished: proving that a person holds a qualification, obtaining the recognition required to practise a regulated profession, and having the right to work and reside in the country. These procedures are related, but they are not interchangeable.
💡 Where the activity concerns a regulated profession, you can consult our guide on the recognition of foreign qualifications in Belgium. For certain highly qualified third-country nationals, the EU Blue Card in Belgium may also be relevant.
Practical examples
A German company obtains a six-month contract in Portugal
A German company needs to post five technicians to Portugal for six months to perform a contract. Before sending the workers, it is not enough to arrange the travel and apply for an A1 certificate. The company must first check whether the conditions for maintaining Spanish social security legislation are met and obtain the relevant certificate. At the same time, it must assess whether a national posting declaration is required, which Belgian salary and employment conditions apply and whether there are any sector-specific formalities. ESSPASS could make it easier in the future to manage and verify the A1 certificate, but it will not replace this prior assessment.
An employee works regularly in several Member States
A technician who regularly works in Spain, France and Belgium may be in a different situation from a temporary posting. Instead of treating each trip automatically as a separate posting, the company should examine the rules applicable to activities normally carried out in two or more Member States. A digital tool can simplify administration, but it does not replace the legal assessment of the worker’s actual situation.
A Belgian company recruits a professional with a foreign qualification
The company must determine whether the position involves a regulated profession and, if so, what recognition or authorisation the candidate needs. If the candidate is also a third-country national, the company must examine the immigration position and the rules governing access to employment. The proposals on qualifications may simplify part of this process.
A Spanish company posts technicians to Belgium for six months
A Spanish company temporarily sending several workers to Belgium must check whether they can remain subject to Spanish social security and apply for the corresponding A1 certificates. The company must also review the Belgian requirements, including the LIMOSA declaration, applicable employment conditions and any sector-specific requirements. ESSPASS may in the future make the management and verification of the A1 certificate easier.
How can Arthur & Marin assist with the posting of workers and A1 certificates?
An international posting may involve social security, employment law, immigration and international law at the same time. At Arthur & Marin, we analyse these issues together so that the company can determine, before the assignment begins, which procedures must be completed and which documents must be kept.
We can assist from the planning stage through to support during an inspection, including the applicable social security regime, review of the A1 certificate, LIMOSA declarations, Belgian employment conditions, third-country nationals, work and residence permits, and representation before the authorities when an issue arises.
If your company is planning to post workers or already has staff temporarily carrying out activities in another country, Arthur & Marin can review the file and determine the applicable obligations before an issue arises during an inspection or control. Our International Law and Business legal advisory teams assist both with the planning of postings and with issues that arise afterwards.
💡 To prepare for a consultation, it is useful to gather the planned dates, the countries involved, the activity to be carried out, the identity of the employer and host client, and the available employment and social security documentation.
Frequently Asked Questions (FAQ) on the digital A1 certificate and ESSPASS
Will ESSPASS replace the A1 certificate?
No. The A1 will remain the document confirming which social security legislation applies to the worker. ESSPASS is intended to facilitate its application, storage, presentation and verification through a common European digital system.
Is an A1 certificate necessary for a posting of only a few days?
Even a short assignment may require an assessment of which social security legislation applies. For this reason, the situation should be reviewed before the worker starts providing services in another Member State.
Does an A1 certificate automatically allow a worker to work in another EU country?
No. The A1 only confirms which social security system applies to the worker. The company must separately check the labour, administrative and immigration obligations of the destination country. These may include a prior posting declaration, specific salary requirements, documentation obligations, work permits or sector-specific requirements.
Can each Member State require a different posting declaration?
Yes. Although the posting of workers is governed by common EU rules, each Member State has its own administrative procedures. For example, Belgium uses the LIMOSA declaration, while other Member States have different platforms and systems. Before the activity begins, the company should check which declaration is required in the destination country and when it must be submitted.
Will ESSPASS replace national posting declarations?
No. ESSPASS concerns the digitalisation and verification of social security documents such as the A1 certificate. National posting declarations serve a different purpose and will continue to depend on the legislation of each Member State unless future EU reforms introduce further changes.
What happens if a worker habitually works in several Member States?
Where a person habitually works in two or more Member States, the specific EU social security coordination rules for this type of activity must be examined. The first step is to determine the worker’s actual working pattern.
Who applies for the A1 certificate?
The application is submitted to the competent institution of the State whose social security legislation is intended to remain applicable. In practice, for employees, the employer or its representative usually handles the application. For self-employed persons, the procedure depends on the rules of the competent State.
What happens if the posting changes after it has started?
If the duration, place of work, activity, employer or any other relevant circumstance changes, the company should check whether the initial documentation is still correct. It may be necessary to update the A1 certificate, amend a national declaration or complete additional formalities. Keeping documents that no longer reflect the actual situation may create problems during an inspection.
Can an inspection verify the A1 certificate?
Yes. The authorities may request and verify the existence and validity of the A1 certificate. One of the objectives of ESSPASS is to make this verification faster and easier between Member States through a common digital system. Digitalisation may therefore simplify administration, while also making it easier for authorities to exchange information.
What documents should a company keep during a posting?
This depends on the destination country and the type of activity. As a general rule, it is advisable to keep the A1 certificate, national posting declarations, employment contracts, payslips, information on the place and duration of the assignment and any applicable work or immigration authorisations readily available.
What should a company do before posting workers to another Member State?
It is advisable to review four issues in advance: which social security legislation applies, whether an A1 certificate is required, which administrative and employment obligations apply in the destination country, and whether there are any additional immigration or professional requirements. Carrying out this review before the posting begins makes it possible to correct problems before work starts and reduces the risk of issues arising during an inspection.
