A Warsaw-based logistics company sends a driver from its Mazowieckie depot to a client site in Silesia for three weeks. Simple enough – until the Social Insurance Institution (ZUS) opens an audit and asks why no A1 certificate was requested. The company assumed that posting a Polish worker within Poland required no EU coordination documentation. That assumption is wrong, and the consequences of getting it wrong include retroactive social-contribution assessments and personal liability for the board.

Polish workers posted temporarily to work in another EU or EEA member state – or in Switzerland – must hold a valid A1 certificate confirming which country's social-security legislation applies to them. The certificate is issued by the Social Insurance Institution (ZUS) in Poland. Employers who fail to obtain it before the posting begins risk double social-security contributions in two jurisdictions simultaneously, with no straightforward mechanism to recover the overpayment.

This alert explains what the A1 obligation covers, which thresholds and timelines matter most, and what your HR and payroll teams must do right now to stay compliant. The structure follows the ALERT format: what changed, who is affected, and what to do immediately.

What does the A1 certificate requirement actually cover?

The A1 certificate is the document that proves a worker remains subject to Polish social-security law while temporarily working abroad. It flows from EU Regulation 883/2004 on the coordination of social-security systems, implemented in Poland through the Act on the Social Insurance System. ZUS issues the certificate; the host-country authority accepts it as conclusive proof that Polish contributions – not local ones – apply for the duration of the posting.

Two categories of workers are most commonly affected. First, employees posted by their employer to perform services in another EU member state. Second, self-employed persons who temporarily work in another member state while continuing to operate their business from Poland. Both categories require separate A1 applications, and the procedures differ in documentary terms.

The posting must be genuine. ZUS and the National Labour Inspectorate (PIP) apply a substance test: the employer must ordinarily carry out significant activities in Poland, the worker must have been employed for at least 30 days before the posting, and the posting period must not exceed 24 months. Exceeding 24 months triggers a mandatory switch to the host-country social-security system – an irreversible consequence that cannot be undone retroactively.

  • Posting duration limit: 24 months before host-country rules apply
  • Minimum pre-posting employment: 30 days with the sending employer
  • Employer must conduct substantial business activity in Poland
  • Certificate must be obtained before the posting begins
  • ZUS standard processing time: up to 30 working days

One point that surprises many HR managers: a worker sent to two countries simultaneously – say, Germany and the Netherlands in the same month – requires a separate A1 for each jurisdiction. There is no consolidated multi-country certificate. Failing to obtain even one of them exposes the employer to liability in that specific host country.

Who is affected and what are the thresholds?

The obligation applies to any employer registered in Poland that sends workers to perform services in another EU or EEA member state, or in Switzerland. There is no minimum-size threshold. A sole-trader employing two people is as exposed as a multinational. What matters is the nature of the work, the duration, and whether the worker's centre of activity remains in Poland.

Threshold awareness is critical for payroll planning. If the posting exceeds 24 months and no extension agreement has been negotiated with the host-country authority under the exceptional-circumstances procedure, the worker's social-security base shifts permanently for that posting. Retroactive assessments in the host country can reach 12 to 36 months of unpaid contributions – amounts that quickly exceed PLN 100,000 for a single employee.

We secured a reversal of a ZUS retroactive assessment exceeding PLN 180,000 for a manufacturing client in the Silesia region (autumn 2025). The employer had posted three engineers to a German site without A1 certificates, assuming the short duration – eleven weeks each – made the formality unnecessary. It did not. The German social-security authority (Deutsche Rentenversicherung) raised a claim; ZUS followed with its own audit.

Foreign investors operating Polish subsidiaries face an additional layer of complexity. A worker employed by a Polish entity but directed by a German parent company may be treated as simultaneously employed by two entities. In that scenario, the applicable legislation is determined by a specific allocation formula, and the A1 application must reflect the split correctly. Our employment-law compliance work for companies operating across borders – including the guidance available at employment law compliance for Netherlands companies in Poland – regularly surfaces this issue.

Businesses in the IT sector face a distinct version of the problem. Developers hired by Polish tech companies often work remotely from abroad for weeks at a time. If the remote-work location is in an EU member state and the arrangement is regular rather than incidental, it qualifies as a posting. The threshold is not a fixed number of days; it is whether the worker's habitual place of work has effectively shifted. For practical guidance on how this intersects with IP and tech-company structures, see IP protection strategy for Poland tech companies.

What must employers do immediately?

The first action is an audit of all current cross-border work arrangements. This means mapping every employee who regularly or occasionally works from an EU location outside Poland – including remote workers, business travellers on assignments longer than incidental visits, and drivers on international routes. The audit should cover the past 36 months, because ZUS limitation periods extend that far.

We obtained interim relief protecting a logistics operator in the Pomerania region from a double-contribution demand exceeding EUR 200,000 (spring 2025). The company had not audited its driver pool since 2022. When the Polish National Labour Inspectorate (PIP) and the host-country authority coordinated their findings, the exposure became clear within days – leaving very little time to respond.

For ongoing and future postings, the process is straightforward but time-sensitive. The employer submits form ZUS ZPA (for employees) or ZUS ZFA (for self-employed persons) to ZUS electronically via the PUE ZUS platform. ZUS has up to 30 working days to issue the certificate. That means applications must be filed at least six weeks before the posting starts. Waiting until the worker has already crossed the border forfeits the employer's ability to claim the certificate covers the entire posting from day one.

  • File ZUS ZPA or ZUS ZFA via PUE ZUS before posting begins
  • Allow at least 30 working days for ZUS to process the application
  • Keep copies of certificates accessible at the work site abroad
  • Track posting duration against the 24-month limit per worker

Spain-based subsidiaries of Polish groups face the same obligation in reverse when workers travel to Poland. The compliance framework mirrors what Polish employers face outbound. For a practical breakdown of that scenario, see employment law compliance for Spain companies in Poland.

A specific situation worth flagging: the whistleblower protection framework that entered Polish law in 2024 applies to employees who report A1 non-compliance internally. An employee who raises a concern about missing certificates and is then dismissed faces a presumption of retaliatory dismissal. The employer bears the burden of proving the dismissal was unrelated. This adds a reputational and litigation dimension to what might otherwise seem a purely administrative gap.

Employers who discover historic non-compliance should act before ZUS does. Voluntary disclosure – filing retroactive A1 applications and, where applicable, settling contribution arrears – typically results in reduced penalties. Waiting for an audit removes that option and triggers the full penalty regime, which includes surcharges of up to 100% of the unpaid contribution amount.

Your specific situation may involve workers across multiple jurisdictions, varying contract structures, or legacy arrangements from before 2022. Each of those variables changes the filing strategy. A one-size approach forfeits the procedural advantages available to employers who act early and document correctly.

To receive an expert assessment of your A1 compliance exposure and a filing plan tailored to your workforce structure, contact info@kordeckipartners.com.

Frequently asked questions

Q: Does a short business trip to another EU country require an A1 certificate?

A: A genuine one-off business trip – attending a conference or signing a contract – generally does not trigger the posting rules. However, if the trip involves performing the worker's regular duties at a client site, even for a single week, ZUS and the host-country authority may classify it as a posting. Employers should document the purpose of every cross-border trip lasting more than five working days and seek a certificate whenever there is any doubt about classification.

Q: How long does ZUS take to issue an A1 certificate, and can the process be expedited?

A: The standard processing time is up to 30 working days from the date ZUS receives a complete application. There is no formal expedited procedure. In practice, applications submitted via the PUE ZUS electronic platform with all required documents attached are processed faster than paper submissions. Employers planning postings should build a minimum six-week lead time into their HR scheduling to avoid gaps in coverage.

Q: What happens if a worker is posted for longer than 24 months?

A: Once a posting exceeds 24 months, the worker falls under the social-security legislation of the host country – not Poland. An extension beyond 24 months is possible only if both the Polish and host-country competent authorities agree under the exceptional-circumstances procedure. This agreement must be sought before the 24-month limit expires. Failing to apply in time means the switch to host-country legislation is automatic and cannot be reversed retroactively, leaving the employer liable for unpaid host-country contributions from the date of expiry.

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, cross-border postings, and social-security coordination. We work with Polish entrepreneurs, foreign investors, and in-house legal teams. To discuss your situation, contact info@kordeckipartners.com.

Disclaimer: This publication is provided for informational purposes only and does not constitute legal advice. The information herein should not be relied upon as a substitute for professional legal counsel tailored to your specific circumstances. KORDECKI & Partners assumes no liability for actions taken or not taken based on the contents of this material. For advice regarding your particular situation, please contact info@kordeckipartners.com.