A1 certificate from ZUS: when a company needs it and how to apply

An A1 certificate from ZUS shows which country’s social-security legislation applies when an employee or self-employed person works across borders. It matters for postings, regular work in several states and some cross-border telework arrangements. The correct route depends on the facts — not on the traveller’s nationality or the label ‘business trip’ alone.

What does an A1 certificate confirm?

Under EU coordination rules, one person is normally subject to the social-security legislation of only one state at a time. The default is the state where the work is actually performed, but the posting, multi-state work and exceptional-agreement rules can lead to another result. A1 records the institution’s determination.

• A1 identifies the person, the applicable state and the covered period.
• It is issued for an actual cross-border situation, not once for the whole company.
• It remains binding on institutions and courts of other covered states until the issuing institution withdraws or invalidates it.

When should a company consider A1?

• An employee is temporarily sent from Poland to work in one covered state.
• An employee regularly works in two or more covered states, including certain mobile or remote-working patterns.
• A self-employed person temporarily carries on similar activity in another state or normally works in several states.
• The case may require an exceptional agreement, for example under the cross-border telework framework.
• Civil servants, flight crew, seafarers and other special categories follow dedicated rules and forms.

Posted employee: the Article 12 route

An employee sent by a Polish employer to perform work on its behalf in one covered state may remain under Polish legislation when the expected posting does not exceed 24 months and the person is not sent to replace another posted worker whose posting has ended.

• The employer normally carries out substantial activity in Poland, not only internal administration.
• A direct employment relationship remains in place: recruitment and contract, remuneration, control over the work and the right to dismiss remain relevant.
• The person was already covered by the Polish system before posting. ZUS guidance generally treats at least one month as sufficient for a person hired only for the posting; shorter periods are assessed individually.
• The application and evidence match the real assignment, host entity, country and dates.

Short interruptions such as leave, sickness or training normally do not reset the 24-month limit. Do not split one assignment into artificial periods or assume a new certificate will cure a replacement arrangement.

Employer activity in Poland and the direct link

ZUS can examine where the company has its registered office and administration, where staff are recruited, which law governs contracts, where contracts are performed, how many employees work in Poland and abroad, and what turnover is generated in Poland. Keep evidence ready instead of relying only on a Polish registration address.

Self-employed person temporarily working in one state

A self-employed person can remain under Polish legislation for similar temporary activity abroad when the expected period does not exceed 24 months, they normally conduct substantial activity in Poland and they maintain the conditions needed to resume it here.

ZUS looks at the normal activity in Poland, business infrastructure and continuity, and whether the foreign work is in the same sector and of a similar nature. Its guidance generally refers to at least two months of prior activity in Poland; shorter periods are assessed individually.

Regular work in two or more states

Multi-state work is not a sequence of occasional trips. It is a normal, recurring pattern across at least two states. The institution in the person’s state of residence should be informed and determines the legislation provisionally under the Article 16 procedure.

• Employee: working time and/or remuneration are considered; at least 25% in the residence state is an indicator of a substantial part.
• Self-employed person: turnover, working time, number of services and/or income are considered; 25% is again an indicator, not a standalone test.
• The expected pattern for the next 12 months matters, supported by prior records where available. Marginal activity is disregarded.

If there is no objection from another institution, the provisional determination normally becomes final after two months. Plan enough time for questions between institutions instead of treating A1 as an instant travel document.

Cross-border telework

Regular home working from the employee’s residence state can change the applicable system under the normal multi-state rules. Since 1 July 2023, Poland has participated in the Framework Agreement that may allow the employer-state system to continue when habitual telework in the residence state is at least 25% but less than 50% of working time.

The mechanism is not automatic. Both states must be signatories and all conditions must be met; it excludes self-employed work, regular work in a third state and non-telework activity in the residence state. First request an exceptional agreement on US-36 and, after approval, request A1 on US-34. Verify the current signatory list immediately before filing.

Which ZUS form should be used?

• US-1 — a self-employed person temporarily moves similar activity from Poland to one foreign state.
• US-2 — a self-employed person normally works in two or more states.
• US-3 — an employee is posted from Poland to one foreign state.
• US-4 — an employee normally works in two or more states.

Special situations have separate forms: US-31 for employment in Poland combined with self-employment in another state, US-34 after an exceptional agreement, US-36 to request such an agreement, and US-35 to change or cancel an issued A1. US-54 provides legal-residence information for a third-country national and US-55 residence information for an EU/EEA/Swiss citizen. Use the current eZUS wizard and form catalogue.

How to apply through eZUS

1. Map the actual work pattern, states, dates, residence and employment or business relationships.
2. Sign in to eZUS (PUE/eZUS), open the A1 wizard and select the scenario — not a form guessed from an old article.
3. Complete the application for the named person and add the evidence requested for that route.
4. Sign electronically with a qualified signature, trusted profile or personal signature and submit.
5. Monitor the portal for questions and collect the electronic response. Save the certificate and the case file.

ZUS states that it handles a complete, clear application immediately; a case requiring explanations should be handled within one month, and an especially complex case within two months. These are administrative timeframes, not a promise that every certificate arrives before an unplanned departure.

Documents worth preparing

• Assignment letter, employment contract, host arrangement, role, country and exact dates.
• Evidence that the employer normally conducts substantial activity in Poland and that the direct employment link continues.
• Travel and work schedule, working-time or remuneration allocation, residence facts and expected 12-month pattern for multi-state work.
• For self-employment: registrations, contracts, invoices, business infrastructure and evidence of activity before and after the foreign period.
• Residence and immigration documents required for the person’s nationality and destination.

Third-country nationals

Regulation 1231/2010 can extend EU coordination to a third-country national who legally resides in an EU member state and whose situation is not confined to one state. It does not apply to Denmark, and the EEA, Swiss and UK position must be checked separately. A Polish visa, work permit or residence card alone does not prove entitlement to A1.

Where do the rules apply?

EU coordination covers the EU and, through related arrangements, Iceland, Liechtenstein, Norway and Switzerland. For the United Kingdom, protected pre-2021 situations can fall under the Withdrawal Agreement and new situations under the EU–UK Trade and Cooperation Agreement protocol; the rules are similar but not identical.

For work outside that area, check whether Poland has a bilateral social-security agreement and which certificate it requires. Do not use A1 merely because the employer is Polish.

Business trips and very short work

A conference, meeting, fair or training trip may not be a posting under host-country labour law, but social-security coordination is a separate question. Official EU guidance says the employer should, whenever possible, notify the competent institution and request A1. Do not build a policy around an assumed one-day or one-week exemption.

What A1 does not replace

• A work permit, visa or residence title.
• A host-country posted-worker declaration or local labour-law compliance.
• The European Health Insurance Card or appropriate healthcare cover.
• Tax-residence, payroll withholding or permanent-establishment analysis.
• A ZUS certificate of no arrears or proof that every contribution was paid.

After the certificate is issued

• Check the person, legal basis, states and dates against the real assignment.
• Give the worker access to a copy and keep it available for inspections.
• Verify authenticity and validity through the public ZUS A1 verification service when needed.
• Monitor the assignment, residence, employer and work pattern; an issued A1 is not permission to ignore changed facts.

Changes, cancellation and disputes

Use US-35 through eZUS promptly if data change, the work ends early, the route or employer changes, or the certificate should be cancelled. A host authority that doubts A1 should use the institutional dialogue procedure; while A1 remains valid, it binds the other covered state. A refusal or adverse ZUS decision should be reviewed with its appeal instruction and the actual evidence.

A practical employer workflow

1. Put every planned foreign-work case through one HR/payroll intake.
2. Check the destination, territorial instrument, immigration and labour-law notifications.
3. Classify the social-security scenario and select the current form in eZUS.
4. Collect evidence, file before work whenever possible and respond to ZUS questions.
5. Store A1 with the assignment file and give the person a copy.
6. Set calendar controls for the end date, 24-month limit and changes in the work pattern.
7. Audit recurring travellers and remote workers instead of relying only on formal posting letters.

inPL can coordinate payroll and HR, accounting and process outsourcing, from scenario mapping and evidence collection to deadlines and ongoing controls.

Legal and procedural information verified on 18 August 2026. The Council and European Parliament reached a provisional agreement on amendments to Regulations 883/2004 and 987/2009 on 22 April 2026, but it still requires formal adoption and is not applied in this article as current law. Recheck the regulations, ZUS forms, telework signatories and destination-specific requirements before publication and before each filing.