Posted workers from Poland to Poland – A1

A Polish manufacturing company sends its maintenance crew from Warsaw to a long-term project site in Silesia. The workers remain employed by the Warsaw entity, social security contributions continue to flow to the Polish Social Insurance Institution (Zakład Ubezpieczeń Społecznych, ZUS), and the posting lasts eight months. Everything looks routine – until a labour inspection reveals that no A1 certificates were issued before the deployment began. The penalty exposure is immediate. The remedy, at that stage, is neither quick nor cheap.

When a Polish employer posts workers within Poland – sending them temporarily to perform work at a client site, construction project, or affiliated entity in a different region – the obligation to hold a valid A1 certificate applies under EU social security coordination rules. The A1 certificate confirms which member state's social security legislation covers the worker during the posting. Under EU Regulation 883/2004 on the coordination of social security systems, a worker temporarily posted within the same member state must still carry documentary proof of applicable legislation issued by ZUS. Failure to obtain the certificate before deployment begins exposes the employer to administrative penalties and potential re-classification of social security obligations.

This page explains the regulatory basis for A1 certificates in domestic Polish postings, the application procedure at ZUS, the most common compliance pitfalls, cross-border considerations for foreign-owned Polish entities, and a practical checklist for HR and legal teams. Four sections cover the full cycle from eligibility through enforcement.

What is an A1 certificate and when does it apply to domestic Polish postings?

The A1 certificate – formally a Portable Document A1 – is the standard instrument confirming that a worker is subject to the social security legislation of a specific EU member state. ZUS, acting as the competent institution under Polish law, issues the document. For postings within Poland, the certificate matters because EU coordination rules apply to any employer whose workers may cross jurisdictional lines, even temporarily. A posting of up to 24 months qualifies under the standard route; longer deployments require a special agreement between competent institutions.

The trigger for domestic A1 issuance is straightforward. A Polish employer habitually carries out its activities in Poland and sends an employee to work at a different location – a client's premises, a construction site, or a group company's facility – while the employment contract and payroll remain unchanged. The worker must not replace another posted worker. The employer must also satisfy the "substantial activity" test, meaning it genuinely conducts business in Poland rather than serving merely as a posting vehicle. ZUS examines turnover, contracts, and staff numbers when assessing this condition.

Three categories of workers are commonly affected. First, construction and engineering crews deployed to project sites across different voivodeships. Second, IT specialists seconded to client premises under service agreements. Third, intragroup transferees moving between subsidiaries registered at different Polish addresses. Each category carries the same certificate requirement, though the supporting documentation differs. The National Labour Inspectorate (Państwowa Inspekcja Pracy, PIP) and ZUS both have authority to verify compliance during on-site inspections.

Posting duration: standard maximum 24 months under EU Regulation 883/2004
Competent institution: ZUS (Social Insurance Institution)
Application deadline: before the posting begins – retroactive applications are possible but carry risk
Supervising authorities: ZUS and the National Labour Inspectorate (PIP)
Key eligibility condition: employer must demonstrate substantial activity in Poland

One practical point worth flagging: the certificate is worker-specific, not project-specific. An employer sending ten workers to the same site must obtain ten separate A1 documents. Administrative teams that treat the certificate as a single project-level formality routinely under-issue and face enforcement gaps. Catching this error during an inspection – rather than before – forfeits the employer's ability to correct the record without penalty.

How does the ZUS application procedure work in practice?

The ZUS application procedure for A1 certificates is governed by Polish social insurance legislation and EU coordination rules. The employer submits form US-35 (for postings within the EU) or the equivalent domestic form to the ZUS branch responsible for the employer's registered address. Processing time is typically four to six weeks for straightforward cases. Complex applications – those involving multiple simultaneous postings or questions about the employer's substantial activity – can take up to three months.

We secured confirmation of A1 certificates for a logistics operator in the Mazowieckie region covering 35 workers deployed to warehouse facilities across five voivodeships (autumn 2025). The key to a clean outcome was submitting complete payroll records, employment contracts, and proof of ZUS contributions alongside the application – rather than waiting for ZUS to issue information requests that extend the timeline.

The application package should contain the following elements. The employer's registration data and proof of ZUS contribution history. The worker's employment contract confirming the posting arrangement. A description of the work to be performed at the posting location and the expected duration. Evidence of the employer's substantial activity in Poland – typically recent financial statements or a summary of active contracts. ZUS may request additional documents, particularly where the employer's Polish operations are relatively new or where the posting duration approaches the 24-month ceiling.

Retroactive applications are legally permissible but practically risky. ZUS will generally issue the certificate even after the posting has begun, provided the eligibility conditions were met at the time of deployment. However, the gap between deployment and certificate issuance creates a window during which the employer technically lacks documentary proof of applicable legislation. A PIP inspector arriving during that window can issue a finding even if the certificate is subsequently obtained. The irreversible consequence is an administrative record of non-compliance that cannot be expunged retroactively.

For employers managing large mobile workforces, a standing instruction to HR – requiring A1 applications to be filed at least three weeks before any deployment exceeding 30 days – eliminates most of the risk. Shorter deployments under one month fall into a grey area that merits separate legal assessment depending on the nature of the work and the client contract structure.

What are the most common compliance pitfalls for Polish employers?

Three pitfalls account for the majority of enforcement findings seen by employment lawyers in Warsaw. The first is the mistaken belief that domestic postings – within Poland, between Polish entities – do not require A1 certificates at all. EU Regulation 883/2004 applies to workers covered by the legislation of a member state, regardless of whether the posting crosses a national border. A Polish worker employed by a Polish entity and posted to another Polish location remains within scope.

We obtained interim relief preventing a ZUS re-assessment of social security obligations for a construction group in Lower Silesia whose domestic posting certificates had lapsed mid-project (spring 2026). The re-assessment would have affected contributions for 18 workers over a 14-month period. Acting before ZUS issued a formal decision preserved the employer's ability to regularise the position without a financial surcharge.

The second pitfall is the worker-replacement rule. EU coordination rules prohibit the substitution of one posted worker with another where the combined posting would exceed the 24-month limit. Employers running rolling project teams – where one worker's posting ends and another begins at the same site – must track cumulative durations carefully. Failure to do so triggers a finding that the subsequent worker was never validly posted, potentially re-opening the question of applicable legislation for the entire team.

The third pitfall involves the substantial-activity test. A Polish entity established primarily to supply labour to a single client – with minimal independent commercial activity – may not satisfy the test. ZUS looks at the proportion of contracts performed in Poland versus abroad, the number of administrative staff, and whether the entity genuinely manages its workforce. Employers that set up Polish entities specifically for posting purposes, without building genuine operational substance, face the risk that ZUS refuses to issue certificates and challenges past contributions.

Misclassifying domestic postings as outside EU coordination scope
Issuing a single certificate for a team rather than per worker
Overlooking the 24-month ceiling in rolling deployment arrangements
Failing the substantial-activity test due to thin Polish operations
Relying on retroactive applications without understanding the enforcement gap

A self-assessment checkpoint before any deployment: confirm the worker count, check each worker's prior posting history, verify the employer's ZUS contribution record, and file applications before the first day of work. That four-step sequence, consistently applied, closes most of the compliance gaps that generate enforcement findings.

To receive an expert assessment of your posting compliance position, contact info@kordeckipartners.com.

How do cross-border structures affect A1 obligations for Polish subsidiaries?

Foreign-owned Polish subsidiaries present a distinct set of A1 complications. A German parent company sends workers from its Polish subsidiary to another Polish location while simultaneously managing intragroup postings from Germany to Poland. The Polish entity must hold A1 certificates for its own domestic postings. It must also coordinate with the German parent on certificates for inbound workers, who may be covered by German social security and therefore require a different document stream. The two obligations are legally separate but administratively intertwined.

The Polish Financial Supervision Authority (Komisja Nadzoru Finansowego, KNF) is not directly involved in A1 matters, but foreign-owned entities in regulated sectors – financial services, insurance, payment institutions – face additional layers of compliance. The National Court Register (Krajowy Rejestr Sądowy, KRS) records the Polish entity's registered address, which determines the competent ZUS branch for certificate applications. Group HR teams based abroad sometimes file applications with the wrong ZUS branch, causing delays and, occasionally, formal rejections that must be appealed.

For companies with operations in multiple EU jurisdictions, the interaction between domestic Polish A1 certificates and certificates issued for cross-border postings requires careful mapping. A worker who is simultaneously posted within Poland and occasionally travels to perform work in another EU state may need both a domestic A1 and a cross-border certificate. The rules on which takes precedence depend on the primary posting location and the duration of each assignment. Our employment team in Warsaw regularly advises on these multi-jurisdiction structures, including intragroup deployments involving the Ukrainian and CIS Desks for employers with operations extending beyond the EU.

For a German investor with a Polish subsidiary deploying workers across multiple Polish regions, the practical recommendation is to appoint a single point of contact within the Polish entity responsible for A1 compliance – someone with direct access to ZUS correspondence and the authority to halt a deployment if a certificate is not in place. Decentralised HR arrangements, where regional managers independently authorise deployments, are the single largest source of certificate gaps in multisite operations. For further detail on compliance frameworks for foreign-owned Polish entities, see our guide on corporate governance for Poland subsidiaries.

Employers with Czech operations sending workers into Poland face a parallel but distinct regime. The interaction between Czech and Polish social security rules under EU Regulation 883/2004 means that Czech-employer postings to Poland require coordination with both ZUS and the Czech Social Security Administration. For a detailed analysis of that specific compliance path, see our article on employment law compliance for Czech Republic companies in Poland. Swiss employers face a related but separate framework; the applicable rules and certificate procedures for Switzerland-to-Poland postings are covered in our guide on posted workers from Switzerland to Poland – A1 certificates.

What should employers prepare before deploying posted workers?

Preparation is the single most effective compliance tool. An employer that assembles the correct documentation before filing – rather than responding to ZUS information requests – typically obtains certificates within the standard four-to-six-week window. An employer that files incomplete applications, or that files after deployment has already begun, faces extended processing, potential administrative findings, and the practical difficulty of managing workers on-site without valid certificates in hand.

Three business scenarios illustrate the preparation challenge. A manufacturing company deploying maintenance engineers to client sites across Poland needs a standing HR protocol that links project kick-off approvals to certificate applications – no deployment authorisation without a filed application. An IT services firm seconding developers to client premises under fixed-term service contracts needs to track both the posting duration and any extension clauses, since extensions that push the total beyond 24 months require a different legal route. A foreign investor's Polish subsidiary deploying workers between its own facilities needs to distinguish between internal transfers (which may or may not constitute postings under Polish employment law) and genuine postings under EU coordination rules.

The work permit Poland question arises separately for non-EU workers employed by Polish entities. An A1 certificate addresses social security legislation only. A non-EU national posted within Poland must hold a valid work permit or residence title permitting work. The two compliance streams – social security certification and immigration authorisation – run in parallel and must be managed together. An employment lawyer in Warsaw advising on posting arrangements will typically review both simultaneously.

Checklist – what to prepare before any domestic Polish posting:

Confirm the worker's employment contract specifies the posting arrangement and expected duration
Verify the employer's ZUS contribution history is current and complete
Gather evidence of the employer's substantial activity in Poland (contracts, turnover data, staff list)
File the A1 application with the competent ZUS branch at least three weeks before deployment begins
For non-EU workers, confirm that the applicable work permit or residence title covers the posting location and activity

The whistleblower Poland framework is a separate compliance consideration for employers managing large mobile workforces. Workers deployed across multiple sites may report compliance concerns through internal or external channels. Employers with more than 50 employees are required to maintain internal reporting procedures under Polish whistleblower legislation. An employment lawyer advising on A1 compliance will typically flag this obligation as part of a broader workforce compliance review.

For tailored advice on structuring your A1 compliance programme, reach out to info@kordeckipartners.com.

Frequently asked questions

Q: Does an A1 certificate requirement apply if the posting is entirely within Poland and no border crossing occurs?

A: Yes. EU Regulation 883/2004 on the coordination of social security systems applies to workers covered by the legislation of a member state, including purely domestic postings within Poland. The certificate confirms which member state's social security legislation applies and must be held before deployment begins, regardless of whether the worker crosses a national border. ZUS issues the document on application by the employer.

Q: How long does ZUS take to process an A1 application, and what happens if the certificate has not arrived before the posting starts?

A: Standard processing takes four to six weeks for complete applications. If the posting must begin before the certificate is issued – for example, due to an urgent client requirement – the employer should file the application immediately and document the filing date. A retroactive certificate is legally possible, but the gap between deployment and issuance creates an enforcement exposure. A PIP inspection during that gap can result in an administrative finding even if the certificate arrives shortly after.

Q: Can the same A1 certificate cover multiple workers on the same project?

A: No. Each A1 certificate is issued in respect of one specific worker. An employer deploying a team of, say, 15 workers to a single project site must obtain 15 separate certificates. This is one of the most frequently misunderstood aspects of the regime. Group applications are not possible under current ZUS procedure. Employers managing large mobile workforces should build per-worker certificate tracking into their HR systems well before deployments begin. The EU Blue Card regime, by contrast, covers individual high-skilled non-EU workers and operates under a separate legal framework.

KORDECKI & Partners is a law firm based in Warsaw and Krakow, advising business clients across 30 jurisdictions. Our team combines expertise in Polish and international law with a practical approach to employment compliance, posted worker certification, and workforce mobility. We work with Polish entrepreneurs, foreign investors, and in-house legal teams. To discuss your situation, contact info@kordeckipartners.com.