A Bucharest-based construction firm wins a contract in Warsaw. It plans to send 15 Romanian workers to Poland for six months. The question that arises immediately – and that too many companies answer incorrectly – is which social security system applies and how to prove it.
Posted workers from Romania to Poland remain subject to Romanian social security, provided the posting meets EU coordination rules and the employer holds a valid A1 certificate for each worker. The A1 certificate is issued by the Romanian social security authority, Casa Națională de Pensii Publice (National House of Public Pensions, CNPP), and must be obtained before the posting begins. Without it, the Polish Social Insurance Institution (ZUS) may claim that Polish contributions are due for the entire posting period – a correction that can reach hundreds of thousands of PLN and cannot easily be reversed.
This guide walks through the A1 procedure step by step: eligibility conditions, the application process at CNPP, timelines, costs, documentation, and the three most common mistakes Romanian employers make. It also covers what Polish labour inspectors check on site and how to structure the posting agreement correctly.
What is the A1 certificate and why does it matter for Romanian postings?
The A1 certificate is a portable document issued under EU Regulation 883/2004 on the coordination of social security systems. It confirms that a worker remains covered by the social security legislation of their home state – Romania – while temporarily working in another EU member state, here Poland. Without it, the host state's legislation applies by default. For a Romanian employer, that means Polish ZUS contributions from day one.
The financial stakes are concrete. Polish social security contributions total roughly 35% of gross salary when both employer and employee shares are combined. For a team of 15 workers posted for six months at average Romanian wages, the gap between Romanian and Polish contribution bases can translate into a retroactive ZUS liability exceeding PLN 200,000. That liability cannot be waived once ZUS issues a decision; the only remedy is an administrative appeal and, if necessary, litigation before the Social Insurance Court in Warsaw.
The A1 also matters for the Polish National Labour Inspectorate (Państwowa Inspekcja Pracy, PIP). PIP inspectors routinely ask for A1 certificates during site visits. A missing or expired certificate triggers a protocol, a potential fine, and a referral to ZUS. The PIP has the authority to halt work on a construction site pending document verification – a delay that can cost far more than the compliance effort would have.
One further point worth understanding: the A1 is not a work permit. It addresses social security jurisdiction only. Romanian citizens are EU nationals and do not need a work permit to work in Poland. The A1 sits alongside – not instead of – the posting notification obligations discussed below.
Who qualifies for an A1 certificate under Romanian posting rules?
Eligibility rests on four conditions drawn from EU coordination law. The employer must normally carry out substantial activity in Romania. The posting must be temporary, with a standard maximum of 24 months. The worker must not be sent to replace another posted worker. And the worker must have been subject to Romanian social security immediately before the posting begins – typically for at least one month.
The "substantial activity" test is the one most often failed by Romanian employers. CNPP examines whether the company genuinely operates in Romania: turnover generated domestically, number of employees working in Romania, contracts concluded and performed in Romania, and the period of establishment. A shell company created specifically to channel workers to Poland will not qualify. CNPP has tightened scrutiny on this point since 2022, and Polish ZUS cooperates with CNPP under the A1 withdrawal procedure when fraud is suspected.
The 24-month ceiling is firm. If the posting is expected to exceed 24 months, the employer must either apply for an exception under the agreement procedure – requiring approval from both CNPP and ZUS – or accept that Polish social security will apply from month 25. Some employers structure projects in phases to stay within the limit; this is permissible only if there is a genuine break in the posting, not a paper interruption.
- Employer has genuine business operations in Romania (turnover, staff, contracts)
- Worker was insured in Romania for at least one month before posting
- Posting duration does not exceed 24 months
- Worker does not replace a previously posted worker in the same position
- The work is performed for the account and under the direction of the Romanian employer
That last condition – work performed for the account and under the direction of the Romanian employer – is increasingly examined. If the Polish client controls the worker's daily tasks, sets working hours unilaterally, and integrates the worker into its own organisational structure, PIP may requalify the arrangement as a secondment or even a disguised employment relationship with the Polish entity. The distinction matters because it affects both social security and minimum wage obligations.
How do you apply for an A1 certificate at CNPP – and how long does it take?
The application is filed with CNPP, specifically with the territorial pension house (casa județeană de pensii) in the county where the employer is registered. Romania processes A1 applications on a per-worker basis; there is no group application for a team of 15. Each worker requires a separate file. The standard processing time is 30 working days, though in practice Bucharest and Cluj offices often respond within two to three weeks for straightforward cases.
The core documents for each application include: employer registration documents, proof of substantial activity in Romania (financial statements, payroll records, list of domestic contracts), the worker's Romanian social security history, the employment contract or posting addendum, and a description of the work to be performed in Poland including the name and address of the Polish client and the expected duration. CNPP may request supplementary documents; failure to respond within the set deadline results in rejection of that application.
We secured timely A1 certificates for a Romanian civil engineering firm sending 18 workers to a logistics park project in the Mazowieckie region (spring 2025). The key was preparing the substantial-activity dossier before the CNPP filing, rather than assembling documents reactively after the first information request.
The posting notification to the Polish Chief Labour Inspector (Główny Inspektor Pracy, GIP) must be filed separately, through the online portal at pip.gov.pl, before the first day of work. This notification is not part of the A1 procedure but is mandatory under Polish law implementing the EU Posted Workers Directive. The notification requires: employer details, Polish client details, place and type of work, duration, number of posted workers, and the name of a contact person in Poland. Failure to notify GIP carries a fine of up to PLN 30,000 per inspection.
What are the minimum employment conditions Polish law requires for posted workers?
Posting an A1 certificate solves the social security question. It does not solve the employment conditions question. Polish law, implementing Directive 2018/957 (the revised Posted Workers Directive), requires that Romanian employers apply Polish minimum standards to posted workers from day one. The most important are: minimum wage (PLN 4,666 gross per month from January 2026), maximum working time limits, minimum rest periods, health and safety rules, and equal treatment principles.
From month 13 of posting – or from day one for construction sector postings – the full set of Polish employment conditions applies, with the exception of supplementary occupational pension schemes. This "long-term posting" rule catches many Romanian employers off guard. A construction project running 14 months triggers full Polish employment parity on day one, not from month 13. Romanian employers in construction must therefore budget for Polish minimum conditions from the outset.
Holiday pay deserves separate attention. Polish law grants workers 20 or 26 days of annual leave depending on seniority. If the Romanian employment contract provides fewer days, the Polish standard applies for the duration of the posting. PIP inspectors check holiday records. A posting of six months with no holiday entitlement recorded in Polish terms is a red flag.
One practical tool is the posting agreement or addendum to the employment contract. This document should explicitly state: applicable Romanian law as the governing law of the employment relationship, the specific Polish minimum conditions being applied during the posting, the gross salary (which must meet the Polish minimum), and the allowances or benefits paid in connection with the posting. A well-drafted addendum reduces the risk of reclassification and provides clear documentation for both PIP and ZUS inspections.
What are the three most common mistakes – and how do you avoid them?
The first mistake is applying for the A1 certificate after the workers have already started in Poland. CNPP can issue a certificate retroactively in some cases, but ZUS is not obliged to accept it. If ZUS has already opened a social security inquiry, a late A1 may not prevent a contribution assessment. The posting must be notified to GIP before it begins; the A1 should be in hand before that notification is filed.
The second mistake is treating the A1 as a static document. If the posting is extended, a new A1 must cover the extension period. If the worker returns to Romania for more than a temporary interruption and is then sent back, a fresh A1 is required. Employers who extend projects by simply continuing the original A1 beyond its stated end date are exposed to ZUS assessments for the uncovered gap period.
The third mistake – and the most expensive – is failing to maintain the documentary infrastructure in Poland. PIP inspectors have the right to demand, during a site inspection, the A1 certificates, the GIP notification confirmation, the posting addenda, payroll records showing Polish minimum wage compliance, and working time records. These documents must be available in Polish or with a Polish translation. Employers who keep records only in Romanian, or only at headquarters in Bucharest, face fines and project suspensions. The obligation to maintain records in Poland lasts for two years after the posting ends.
We obtained a reversal of a ZUS contribution assessment exceeding PLN 350,000 for a Romanian IT services company operating in the Małopolska region (autumn 2024). The assessment arose because the company's A1 certificates had expired mid-project and no renewal had been filed. The appeal succeeded on procedural grounds, but the process took 14 months. Prevention – a renewal calendar and a compliance check before each project phase – costs a fraction of that effort.
For Romanian employers working across multiple EU jurisdictions, it is also worth reviewing how the Polish posting interacts with the Romanian tax treatment of the posted workers' remuneration. The A1 confirms social security jurisdiction; income tax follows separate rules under the Romania-Poland double tax treaty. These two questions must be answered independently.
To receive an expert assessment of your posting structure and A1 compliance, contact info@kordeckipartners.com.
Three business scenarios: construction, IT, and foreign investor
Each of the following scenarios illustrates a distinct compliance profile. The underlying legal framework is the same; the practical risks differ significantly.
Scenario 1 – Romanian construction contractor. A Timișoara-based company sends 20 workers to a Warsaw office development for 18 months. Construction is the highest-risk sector for posting compliance in Poland. PIP runs targeted inspection campaigns on construction sites. The employer must hold A1 certificates for all 20 workers, file the GIP notification before day one, apply Polish minimum wage and health-and-safety rules from day one (construction triggers full parity immediately), maintain a site documentation folder accessible to inspectors, and designate a Polish-speaking liaison. The liaison need not be a lawyer but must understand what documents PIP can demand and where they are kept.
Scenario 2 – Romanian IT services firm. A Cluj-based software house seconds three developers to a Polish fintech client in Warsaw for 12 months. The A1 procedure is the same, but the practical risks differ. The main risk here is reclassification: if the Polish client controls the developers' tasks directly, sets their hours, and integrates them into its teams, PIP or ZUS may treat the arrangement as a staffing agency operation or a direct employment relationship with the Polish entity. The posting addendum must clearly preserve the Romanian employer's direction and control. The EU Blue Card is not relevant here – EU nationals do not need it – but the employer should confirm that no non-EU sub-contractors are involved, as that triggers separate work permit obligations under Polish immigration law.
Scenario 3 – German investor with Romanian subsidiary. A German group uses its Romanian subsidiary to post workers to its Polish subsidiary. This intra-group posting is permissible, but the substantial-activity test applies with full force. CNPP will examine whether the Romanian entity genuinely employs the workers and carries out real business in Romania. A Romanian subsidiary that exists primarily as a payroll vehicle will not satisfy the test. The group should document the Romanian entity's own operations: separate management, local contracts, Romanian payroll history. For guidance on how cross-border insolvency issues can complicate intra-group structures, see our analysis at cross-border insolvency involving Poland and Romania.
Across all three scenarios, the whistleblower protection framework in Poland is relevant. Since 2024, Poland's whistleblower legislation has been in force. A posted worker who reports posting violations – underpayment, missing A1, false GIP notification – is protected from retaliation. Romanian employers should be aware that their Polish client's internal reporting channels may receive such reports. Employment lawyers in Warsaw increasingly advise Polish clients to include posting compliance in their whistleblower policy scope.
For a comparison with posting structures from other EU jurisdictions, see our guide on employment law compliance for Spain companies in Poland and our parallel analysis of posted workers from Cyprus to Poland – A1 certificates.
Your specific posting structure may involve combinations of these scenarios – a Romanian contractor using subcontractors, or a mixed team of Romanian and third-country nationals. Each variation requires individual analysis. To discuss how the posting rules apply to your situation, email info@kordeckipartners.com.
Frequently asked questions
Q: Can we start the posting before the A1 certificate is issued?
A: Starting the posting before the A1 is issued creates a compliance gap. ZUS treats the period without a valid A1 as a period in which Polish social security applies. CNPP can issue a certificate with a start date matching the actual start of posting, but ZUS acceptance of a retroactive certificate is discretionary and not guaranteed. The safest approach is to apply to CNPP at least four weeks before the planned start date and to delay the posting if the certificate has not arrived.
Q: How much does the A1 procedure cost, and who bears the cost?
A: CNPP does not charge a fee for issuing A1 certificates. The cost is the administrative effort of preparing the substantial-activity dossier and the per-worker application files. For a team of 15 workers, employers should budget for 10 to 20 hours of legal and HR preparation time, plus translation costs if documents are in languages other than Romanian. The GIP notification in Poland is also free. Legal advisory fees for structuring the posting, drafting the addenda, and reviewing compliance vary; a fixed-fee engagement for a standard posting of up to 20 workers typically falls in the range of EUR 1,500 to EUR 3,000.
Q: Does the A1 certificate cover the worker's family members who accompany them to Poland?
A: The A1 certificate covers the worker's own social security status. Family members who do not work in Poland are generally covered under the worker's Romanian health insurance through the derived-rights mechanism under EU coordination rules. However, family members who take up employment in Poland – even part-time – need their own social security assessment. This is a common misconception: employers sometimes assume the worker's A1 extends to all household members, which it does not.
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, posted workers compliance, and cross-border mobility. 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.