Posted workers from Poland to Poland – A1

A Warsaw-based IT services company seconds a Polish national to work at a client site in Kraków. The employee remains on the Polish payroll. No one thinks to apply for an A1 certificate. Six months later, a Social Insurance Institution (ZUS) inspection reveals the gap – and the company faces surcharges, interest, and reputational exposure it could have avoided entirely.

Posted workers from Poland to Poland present a compliance puzzle that many employers overlook. Where a Polish employer seconds an employee to perform services in a different Polish region or city while the employee's social security contributions remain with ZUS, an A1 certificate may still be required if that employee simultaneously works or resides in another EU member state. The certificate is issued by ZUS and confirms the applicable social security legislation, preventing double contributions across borders. Failure to obtain it on time exposes employers to penalties and personal liability for unpaid contributions.

This guide walks through the A1 certificate procedure step by step – from eligibility conditions and documentation to timelines, costs, and the three most common mistakes Polish employers make. We also address cross-border scenarios where a posting within Poland intersects with EU social security coordination rules under Regulation (EC) No 883/2004.

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

The A1 certificate is the official document confirming which EU member state's social security system applies to a worker at a given time. ZUS issues it for Polish workers. It matters whenever a worker is active in more than one EU country – or when a Polish employer posts a worker abroad, even temporarily. The certificate prevents the employer from paying contributions twice: once in Poland and once in the host country.

The situation becomes genuinely complex when a posting is described as "within Poland" but the employee also performs part of their duties in Germany, the Netherlands, or another EU state. In that scenario, EU coordination law applies in full. The employer must demonstrate that the employee ordinarily works in Poland. ZUS will assess the employer's registered seat, turnover structure, and the employee's habitual residence before issuing the certificate.

Three conditions must be met before ZUS will issue the A1 document:

The employee must be subject to Polish social security legislation at the time of the application.
The posting must not exceed 24 months (for standard postings under EU coordination rules).
The employee must not be sent to replace another posted worker whose posting period has not yet ended.

Poland's National Court Register (KRS) records are often the first document ZUS requests to confirm the employer's genuine business activity in Poland. The Polish Financial Supervision Authority (KNF) and the Social Insurance Institution (ZUS) coordinate on cases involving financial sector employers. Employers registered only for posting purposes – so-called "letterbox companies" – will be refused. The 24-month cap is firm. Extensions require a bilateral agreement between the competent authorities of both member states involved, and ZUS will not grant them unilaterally.

One concrete figure to keep in mind: ZUS must receive the A1 application before the posting begins, or at the very latest on the first day of the posting. Late applications do not automatically result in refusal, but they do trigger closer scrutiny and may delay issuance past the inspection window – leaving the employer exposed during that gap.

How do you apply for an A1 certificate through ZUS?

The application process involves three distinct phases: documentation assembly, submission to ZUS, and certificate issuance. Each phase carries its own timeline. Employers who treat this as a one-page form submission consistently encounter delays. The entire process, done correctly, takes between 14 and 30 days for straightforward cases. Complex cross-border structures can extend that to 60 days.

Documentation assembly is where most errors occur. The employer must prepare a complete posting package for ZUS. This typically includes the employment contract, confirmation of Polish social security registration, evidence of the employer's genuine business activity in Poland (payroll records, tax filings, client contracts), and the employee's habitual residence declaration. For workers who are also performing duties in another EU state – which is the scenario that triggers A1 obligations most often – the employer must also document the percentage of working time spent in each country.

The submission itself is made on ZUS form US-36 (for postings to another EU member state) or the equivalent form for workers covered by bilateral social security agreements. The form must be submitted to the ZUS branch competent for the employer's registered seat. Online submission through the ZUS PUE portal is available and significantly reduces processing time. Paper applications add 5 to 10 business days to the queue.

We obtained a full set of A1 certificates for a logistics operator in the Mazowieckie region (autumn 2025), covering 34 drivers who performed cross-border routes while remaining on the Polish payroll. The key was pre-assembling the route documentation and habitual residence declarations before any ZUS contact – cutting the issuance timeline from an estimated 45 days to 19.

Once ZUS issues the certificate, the employer must retain a copy and provide the original to the employee for presentation to foreign authorities on request. The certificate is valid for the duration stated on its face – up to 24 months. Employers should calendar a renewal review at least 60 days before expiry. Missing the renewal window does not invalidate the original certificate, but it creates a gap in coverage that inspectors in host countries will note.

What are the most common mistakes employers make with A1 certificates?

Three errors account for the overwhelming majority of A1 compliance failures in Poland. Each is avoidable. Each carries consequences that range from administrative inconvenience to personal liability for the company's management board.

The first mistake is assuming that a posting "within Poland" cannot trigger EU coordination rules. It can – and does – whenever the employee also works in another EU state, even occasionally. A software developer based in Warsaw who attends quarterly client meetings in Berlin is working in two EU states. The employer's failure to obtain an A1 certificate for that developer means the developer is technically uninsured in Poland for EU coordination purposes. If the developer is injured during the Berlin visit, the resulting dispute over applicable legislation can take years to resolve. Personal liability for unpaid contributions falls on the board.

The second mistake is treating the A1 certificate as a one-time task. Postings are renewed. Employees change roles. Some workers move from full posting status to simultaneous employment in two countries – a situation that requires a different certificate category altogether (the "two or more states" category under EU coordination rules). Employers who issue a single certificate and never review it again routinely find themselves out of compliance within 18 months.

The third mistake is failing to document the employer's genuine business activity in Poland. This is the "letterbox company" trap in reverse: a genuine Polish employer with real operations may still fail the ZUS documentation test if its HR team cannot produce the required evidence quickly. ZUS inspectors give employers a short window – sometimes as little as 7 days – to produce documentation during an audit. Employers who cannot respond within that window are treated as non-compliant regardless of their actual payroll status.

For context on how similar issues arise in inbound posting scenarios – where workers come to Poland rather than leave it – the procedural framework shares many features with the outbound A1 process. Our article on posted workers from Spain to Poland and A1 certificates sets out the parallel obligations for employers on the receiving end of a cross-border posting.

To receive an expert assessment of your company's A1 certificate exposure, contact info@kordeckipartners.com.

Your specific compliance gap may already be generating liability. A missed A1 certificate does not become visible until an inspection – at which point the employer has no option to retroactively cure the gap without penalty. Early review forecloses that risk entirely.

How do A1 obligations differ across three business scenarios?

The A1 certificate rules apply differently depending on the employer's structure, the employee's work pattern, and the countries involved. Three scenarios illustrate the range of situations Polish employers face.

In the manufacturing scenario, a Silesian metalworks company sends a maintenance engineer to its German client site for three weeks each month. The engineer is on a Polish employment contract and pays ZUS contributions in Poland. This is a classic single-state posting: the engineer works predominantly in Poland (the remaining time) and is temporarily posted to Germany. The employer applies for an A1 certificate on form US-36 before the first trip. ZUS issues it within 21 days. The certificate covers up to 24 months. The employer retains documentation of the engineer's Polish working time to rebut any future challenge.

In the IT services scenario, a Warsaw-based software house has developers who work remotely from Poland but attend monthly sprints at a client office in Amsterdam. Each developer spends roughly 15 percent of their working time in the Netherlands. This is a "two or more states" situation under EU coordination rules. The employer must apply for a different certificate category. ZUS will assess whether Poland remains the state of habitual residence and whether the employer's principal place of business is genuinely in Poland. The process takes 30 to 45 days and requires more detailed documentation than a standard posting application.

In the foreign investor scenario, a German group establishes a Polish subsidiary to employ workers who will service clients across Central Europe. The subsidiary is registered with KRS but has only three employees and minimal Polish revenue in its first year. ZUS will scrutinise whether the subsidiary constitutes genuine business activity in Poland. If ZUS determines that the subsidiary is a letterbox structure, it will refuse A1 certificates – and the German parent may face contribution obligations in multiple EU states simultaneously. Structuring the subsidiary correctly from the outset, with real operational substance in Poland, is the only reliable solution. This connects directly to the broader B2B reclassification risks that Polish employment law practitioners flag regularly; our analysis of B2B reclassification risk and PIP enforcement powers in 2026 covers the enforcement environment in detail.

We assisted a foreign-owned logistics group in Pomerania (spring 2026) in restructuring its Polish employment arrangements to satisfy ZUS's genuine business activity requirements. The outcome: 12 A1 certificates issued within 25 days, covering drivers on international routes previously flagged by the German Zollamt as potentially uninsured.

What should employers prepare before filing an A1 application?

Preparation determines speed. Employers who assemble the full documentation package before contacting ZUS consistently receive certificates faster and face fewer follow-up requests. The checklist below reflects the standard ZUS documentation requirements for Polish outbound postings.

Employment contract or appointment document confirming the employee's Polish social security registration number (PESEL or NIP).
Evidence of ZUS contribution payments for the preceding three months (ZUS DRA declarations or equivalent payroll records).
Proof of the employer's genuine business activity in Poland: KRS extract, recent tax returns (CIT or PIT-4R), and at least two client contracts executed in Poland.
The employee's habitual residence declaration, signed and dated, confirming the employee's primary address in Poland.
Posting agreement or secondment letter specifying the host country, posting duration, and the employee's duties abroad.

The habitual residence declaration deserves particular attention. ZUS does not accept a Polish address alone as proof of habitual residence. The declaration must be supported by evidence: utility bills, a lease agreement, or a Polish bank account statement. Employees who have recently relocated from another EU state will face additional scrutiny. ZUS may request documentation of the employee's centre of life interests – a concept borrowed from EU coordination law that looks at family ties, property ownership, and the duration of residence in Poland.

One practical point on costs: ZUS does not charge a fee for issuing A1 certificates. The employer's costs are entirely internal – staff time, legal fees if external counsel is engaged, and translation costs for supporting documents originally in a foreign language. For a straightforward single-employee posting, a competent HR team can manage the process in-house. For multi-employee postings, cross-border structures, or cases involving ZUS scrutiny of genuine business activity, external legal support typically pays for itself by reducing the risk of refusal and the delay costs that follow.

Employers in regulated sectors should also be aware that the Labour Inspectorate (Państwowa Inspekcja Pracy, PIP) has expanded its coordination with ZUS on A1 compliance checks. An employment inspection that begins as a routine workplace audit can quickly become a social security investigation if the inspector finds gaps in posting documentation. For a broader view of how PIP's enforcement powers are developing, our guide on expert witnesses in Polish court proceedings provides relevant context on evidentiary standards in employment disputes.

For a tailored strategy on A1 certificate compliance, reach out to info@kordeckipartners.com.

The gap between a correct A1 application and an incomplete one is often a single missing document. That gap, left unaddressed, precludes the employer from defending against a ZUS surcharge assessment – an irreversible consequence once the inspection period closes.

Frequently asked questions

Q: Can an employer apply for an A1 certificate retroactively after a posting has already started?

A: ZUS accepts late applications, but they do not eliminate the compliance gap that existed before the application was submitted. The employer remains exposed to contribution assessments and interest for the period between the start of the posting and the date of the application. The practical rule is to apply before the posting begins – or on the first day at the very latest. Retroactive applications also trigger closer documentary scrutiny from ZUS, which typically extends the issuance timeline to 45 days or more.

Q: How much does it cost to obtain an A1 certificate in Poland, and how long does the process take?

A: ZUS charges no fee for issuing the certificate. The employer's out-of-pocket costs are limited to internal staff time and, where external counsel is engaged, legal fees. A well-prepared application for a single employee in a straightforward posting scenario is typically processed within 14 to 21 days. Multi-country or complex structures involving ZUS scrutiny of genuine business activity can extend the timeline to 60 days. Engaging an employment lawyer in Warsaw with ZUS experience reduces the average issuance time by eliminating back-and-forth requests for missing documentation.

Q: Does a Polish employer need an A1 certificate if the employee works entirely within Poland and never travels abroad?

A: If the employee works exclusively in Poland, performs no duties in any other EU member state, and has no employment relationship with any foreign entity, no A1 certificate is required. The certificate becomes necessary only when EU social security coordination rules are engaged – that is, when the worker is active in more than one EU country, or when the employer posts the worker to another EU state. A common misconception is that remote working from Poland for a foreign employer does not engage these rules. It does, and employers in that situation should obtain an A1 certificate to confirm that Polish legislation applies.

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 law, global mobility, and social security compliance. We work with Polish entrepreneurs, foreign investors, and in-house legal teams on A1 certificate procedures, work permit applications in Poland, EU Blue Card filings, and whistleblower protection compliance under Polish law. To discuss your situation, contact info@kordeckipartners.com.