The A1 document: where your contributions belong

EU membership and rights · Last reviewed: 2026-08-23

The single applicable legislation principle

The EU does not merge member states' social security systems. Instead it sets rules deciding which system a person with links to several countries belongs to. The governing principle is „single applicable legislation“: contributions are not owed in two countries for the same period, and being owed nowhere is not accepted either. As a rule a person is subject to the legislation of the country where they ACTUALLY work; the A1 document appears precisely in the situations that depart from that basic rule.

The document's practical value is this: at an inspection abroad, the only valid way to tell an inspector „I am already insured in another member state“ is to produce the A1. A verbal statement, an employment contract or a payslip will not do the job. Without it, the country where the service is provided may apply its own legislation — meaning contributions can be charged a second time for the same work.

Two typical situations: posting and multi-state work

The detail in the posting rule matters: the employer must normally carry out its activities in the sending state, and the posted person must not be replacing another posted person whose period has expired. So the scheme of „set up a paper company and send the worker abroad“ falls outside the rule — and it is the first thing inspections look at.

The multi-state rule now touches ever more people: drivers in international transport, consultants with clients in two countries, remote workers who spend part of the year in Bulgaria and part in another member state. What decides is where the activity is pursued and where the employer is; the calculation follows specific rules and the outcome is determined by the institution, not by you.

What the A1 does not cover — four common confusions

• •It is not a work permit. If you are a third-country national, an A1 does not give you the right to work in another member state; that right comes from migration law. The A1 says only where contributions belong.
• •It is not a health card. Access to healthcare runs on other documents: the EHIC for temporary stays, S1 once you live somewhere. You may need those even while holding an A1.
• •It is not a tax document. Social security and taxation are separate regimes with different tests. Contributions being paid in Bulgaria does not automatically mean your income tax arises here. The tax side is a separate article's subject.
• •It is not a residence document. Your right to stay in a country comes from the residence and entry regime; the A1 says nothing about it.

How to obtain an A1 in Bulgaria

1. 1

   Pick the right institution

   In Bulgaria the certificate on applicable social security legislation is issued by the National Revenue Agency (NRA). Pensions and other benefits fall to the National Social Security Institute; for the A1 the addressee is the NRA.
2. 2

   File the request electronically or on paper

   The NRA offers the service „request for issuing a certificate on applicable social security legislation“ both at its offices and through its electronic services portal. The electronic route also makes the file easier to track.
3. 3

   State the right situation and the right article

   The request form requires you to indicate whether this is a posting or work in several countries. The wrong choice means the document must be reissued and time is lost.
4. 4

   Describe the employer and the activity in full

   The institution assesses whether the employer normally operates in the sending state and where the work will be carried out. Incomplete information means refusal or further correspondence.
5. 5

   Keep the decision and watch its period

   The document is issued for a set period. Check before it lapses whether renewal or extension is needed; work performed after expiry counts as uncertified.

The cost of travelling without the document

A missing A1 looks like a formality and is not. The sectors where inspections concentrate are well known: construction, transport, any work with a chain of subcontractors. If someone is found working without the document, the country where the service is provided may apply its own legislation; that means retroactive contributions, administrative penalties and a breach of the employer's contractual obligations. It also leaves open which country covers an accident or illness — and that is the painful consequence.

Another frequent mistake is assuming the employer obtained it. In a posting the request is normally filed by the employer, but a self-employed person files their own. Where a person works in two countries, responsibility is split less obviously. Before setting off, answer clearly: „who requested this document and do I hold a copy?“ A document that does not exist cannot be produced at an inspection.

Who this right is for

The coordination regulations do not cover everyone equally, and this section is here so you can place your own case correctly.

• •EU, EEA and Swiss nationals. They are the primary addressees of the coordination rules; the A1 works directly within that framework.
• •Third-country nationals legally resident in Bulgaria. Regulation (EU) No 1231/2010 brings within the coordination rules third-country nationals who would otherwise fall outside them solely because of their nationality, provided they are legally resident in the territory of a member state and their situation is not confined in all respects within a single member state. So an A1 can arise for a Turkish, Ukrainian or Russian national holding a residence permit here when posted to another member state. Remember that the regulation does not apply in relation to Denmark; for EEA states and Switzerland the scope may work differently — confirm with the institution according to the destination country.
• •Work in Ukraine or Russia. EU coordination does not cover these countries. Bilateral social security agreements, where they exist, apply instead; check with the National Social Security Institute which agreement is in force and what it covers. No A1 is issued for countries outside the EU framework.
• •Work on the Türkiye axis. Between Türkiye and Bulgaria the social security relationship flows from the bilateral agreement, not from the EU coordination regulations. That means a different document and a different institution; do not assume the EU periods and scope by analogy.

After you have the document

• •Keep one copy with the worker and one with the employer; inspections happen where the person is.
• •If conditions change (the period is extended, a country is added, the employer changes), notify the institution — the document was issued for the old situation.
• •Keep the document's period and the contract's period in the same calendar; a mismatch between them is the commonest inconsistency.
• •Arrange the health side separately: EHIC for a temporary stay, S1 once you live there.
• •Aggregating insurance periods for a pension is a separate topic; A1 periods later serve as proof, so keep the paperwork.

The information here is tied to its sources as of 23 August 2026. Coordination rules and national practice can change; before applying, confirm the current position on the NRA's own service page and on the EU's Your Europe portal. This text is not legal advice.

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