What an A1 certificate is
An A1 certificate, officially the portable document A1 or PD A1, is the form that shows which country's social security legislation applies to you. Your Europe describes it as proof that you remain covered by your home country's system while you work in another EU country, and says the host country's authorities must recognize a valid one.
It belongs to the EU's social security coordination rules, Regulations 883/2004 and 987/2009, which have applied since 2010 and cover the EU plus Iceland, Liechtenstein, Norway and Switzerland, with specific rules for the United Kingdom (European Commission). The A1 replaced the old E 101 form (European Commission FAQ).
The A1 is issued by the country whose system covers you, never by the host country, and only on an application made in time; an institution that receives an application it is not competent for names the country that is, or forwards the application there (Czech Social Security Administration).
What an A1 does not cover: income tax and healthcare
An A1 settles social security contributions and nothing else. Income tax on your salary or profit still follows your tax residence and the treaty between the countries involved, so your income tax as a digital nomad can be due in a different country from your contributions. Investment income sits outside the A1 as well: the tax on crypto you sell while abroad or on shares and property sold after a move depends on where you are resident when you sell, and for property also on where it sits.
A tax residency certificate proves where you are taxed as a resident and the A1 proves where you pay contributions, so you may need both, issued by 2 different countries.
Healthcare runs on its own forms. Your Europe points posted workers to the European Health Insurance Card, and anyone who moves their residence to the host country to a PD S1, registered with that country's health authorities.
A Madrid developer on a 10-month project in Milan
Reads the A1 correctly
Her Madrid employer requests the A1 before she flies, so she stays in Spanish social security for the 10 months. She then checks separately, under Spanish and Italian tax law and the Spain-Italy tax treaty, which country taxes her salary for the work done in Milan.
Reads it as a tax exemption
She treats the A1 as proof that Italy cannot touch her pay and never looks at Italian income tax. The A1 only stops Italian social contributions; 10 months of work in Milan is a separate income tax question, and the A1 does not answer it.
Who needs an A1 certificate
Anyone whose work touches 2 or more countries of the EU, the EEA or Switzerland can need one. Only 1 country's system covers you at a time, and these are the situations that decide which:
Which country's social security covers you, by situation
| Situation | System that covers you |
|---|---|
| Employee sent abroad by the home employer for up to 24 months | Home country, shown by an A1 |
| Self-employed person doing similar work in another country for up to 24 months | Home country, shown by an A1 |
| Working in 2 or more countries, at least 25% of time or income in the country of residence | Country of residence |
| Employee in 2 or more countries, under 25% in the country of residence | Country of the employer's head office or place of business |
| Self-employed in 2 or more countries, under 25% in the country of residence | Country where the center of interest of the activities lies |
| Employed in 1 country and self-employed in another | Country where you are employed |
| Teleworking from home under 50% of working time, when your country and your employer's country have both signed the telework agreement | Employer's country, on a joint request |
| Business trip: meeting, conference, fair or training | Home country; not a posting, but an A1 is requested |
For the self-employed, the 25% can also be measured in turnover and the number of services provided, not only working time and income (Your Europe). Civil servants, flight crew and people employed on board ships get A1s as well (Czech Social Security Administration).
A1 for posted workers: the 24-month rule
A posted employee keeps the home system while working abroad for the home employer. The Your Europe guide to posting staff abroad sets 2 limits: the worker must, as a general rule, be registered in the home system for at least 1 month before the posting (shorter periods are allowed case by case), and the maximum period on the A1 is 24 months.
The employer requests the A1 from the institution where the employee is insured, with the start and end dates of the posting (Your Europe posting guide), and the European Commission says it should apply before the posting starts. The worker should be able to show the A1 to the host country's authorities at any time during the stay (Your Europe).
Past 24 months there are 2 routes: join the host country's system, or ask the institution that issued the A1 for an extension, which is not automatic and needs a mutual agreement between the home and host countries (Your Europe). After coming home, a new posting can follow a gap, and 2 months is considered sufficient by many EU countries (Your Europe).
The posting declaration is a separate filing
The A1 comes from the home country's social security institution. The posting declaration is a different duty: before the posting begins, or at the latest when it starts, the employer notifies the host country's authorities of who it is, a contact person, how many workers it sends, the workplace address, the start and end dates, the type of service, and a contact person for the host authorities (Your Europe). An employer that files only the A1 has still missed the declaration.
A1 certificate for the self-employed
The posting rule also covers freelancers who temporarily do similar work in another country (European Commission). You can post yourself for up to 2 years and stay in the home system, and you apply for the A1 yourself, in advance, to your home country's institution.
Your Europe sets 3 conditions. You must already have worked as self-employed in the home country, for a period that varies by country and can be as little as 2 months; the work abroad must be similar to the work at home; and you must still meet the requirements to carry on that self-employment when you return.
The rule covers a temporary stint only. A freelancer who settles in the new country joins its system, so the contributions move there along with the income tax once you are freelancing from a new base abroad.
A Prague designer working from Berlin
A stint: stays in Czech social security
Self-employed in Prague for 3 years, she spends 5 months in Berlin on a rebrand for a German client, the same work she does at home, and keeps her Czech trade license and her Prague apartment. She applies for an A1 at her local Czech social security office before she leaves and keeps paying in Czechia.
A move: Germany's system applies
She gives up the Prague apartment, signs a Berlin lease and takes on German clients with no end date. That is not a temporary stint, an A1 from Czechia does not fit the facts, and she works only in Germany, so the German system covers her.
Working in 2 or more countries: the 25% rule
Someone who normally works in 2 or more countries at once, rather than on 1 temporary stint, is still insured in only 1 of them. You are covered by your country of residence if you do a substantial part of your activities there, which Your Europe defines as at least 25% of your working time and/or income.
Below 25%, an employee is covered where the employer's head office or place of business is, and a self-employed person where the center of interest of the activities lies (Your Europe). A freelancer who lives in Valencia and does 30% of her work there, the rest on trips to 4 other EU countries, is in the Spanish system, and the A1 comes from Spain.
David's note
For a nomad who works from a new EU country every few months, I would not try to chain A1s from a home system you have already left. I would pick a base, do at least 25% of the work there, and let that country's A1 cover your work in the rest of the EU; it holds up far better when a host country checks.
Outside the EU, the EEA and Switzerland none of this applies, and social security for digital nomads comes down to each country's own law and any bilateral agreement.
Cross-border telework: the 50% framework agreement
Employees who telework from their country of residence for an employer in another country have an extra route. Under a framework agreement on cross-border telework, deposited with Belgium, employer and employee can jointly ask to stay in the employer's system when both countries have signed it and telework in the country of residence is less than 50% of total working time (FPS Social Security).
23 states have signed it: Austria, Belgium, Croatia, Czechia, Estonia, Finland, France, Germany, Ireland, Italy, Liechtenstein, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden and Switzerland. 18 of them apply it from July 1, 2023; Slovenia from September 1, 2023, Italy from January 1, 2024, Lithuania from May 1, 2024, Ireland from June 1, 2024 and Estonia from February 1, 2026, while the UK has said it will not sign (FPS Social Security).
Where the agreement does not apply, the 25% rule decides: an employee working remotely from another country for 25% of the time or more moves into the system of the country where they live. An employer of record that hires you in the country where you live puts you in that country's system like any local employee, with no A1 from home.
Do you need an A1 for a business trip?
Yes, in principle. Attending a conference, meeting, fair or training abroad is not a posting, because no service is provided in the host country, but the Your Europe posting guide says the host country's administration must be informed whenever possible in advance, and the A1 must be requested from the social security administration where the employee is registered.
The posting declaration, by contrast, applies to postings where a service is provided, not to a trip to a trade fair.
How to apply for an A1 certificate
You apply to the institution of the country whose system will cover you, except when you normally work in 2 or more countries at once: then you notify the institution in your country of residence, which decides which country's law applies, and that country issues the A1 (European Commission).
Who issues the A1 in 4 EU countries
| Country | Institution that issues the A1 |
|---|---|
| Germany | Your statutory health insurer (Krankenkasse); the Deutsche Rentenversicherung if you are privately insured, or the ABV if you are also in a professional pension scheme; the DVKA if you live in Germany and work in 2 or more countries (Deutsche Rentenversicherung) |
| France | URSSAF's international mobility service, for employers and the self-employed; the MSA for the farm scheme (CLEISS) |
| Italy | The INPS office where the employer is registered, or where a self-employed person is registered (INPS) |
| Poland | ZUS, with the application filed online through the PUE ZUS portal (ZUS) |
In Czechia it is the local office of the Czech Social Security Administration, picked by the employer's registered or payroll office or the applicant's residence, and an employee's application comes with the employment contracts, the trade license where it cannot be checked, and the contracts for the work in Czechia and abroad.
Getting an A1, step by step
- Name your situation: a posting, a self-employed stint, several countries at once, telework from home or a business trip.
- Confirm which country's system will cover you; that country issues the A1, never the host. If you work in several countries at once, you notify your country of residence first.
- Check the conditions: as a general rule at least 1 month in the home system before a posting, or prior self-employment at home, and an end date within 24 months.
- Apply before the work starts, the employer for a posted employee and you yourself if you are self-employed, with the start and end dates and the contracts the institution asks for.
- For a posting, the employer also files the host country's posting declaration, which is a separate notice.
- Keep the A1 to hand for the whole stay, and ask the issuing institution for an extension before it expires if the work runs longer.
A1 certificates for UK workers after Brexit
The UK still issues the equivalent document. HMRC calls it a certificate of coverage, also referred to as a PDA1, and you keep paying UK National Insurance while working in the EU, Iceland, Liechtenstein, Norway or Switzerland only if HMRC has issued one (GOV.UK).
It covers temporary work of up to 2 years, and also people working in the UK and 1 or more EU countries at the same time. You or your employer apply to HMRC, starting with its interactive guidance tool, which shows which application form your case needs (GOV.UK).
New A1 rules adopted in 2026 (apply from 2028)
The coordination rules have been revised. In April 2026, EU countries approved the text agreed with the European Parliament, which tightens posting: workers must be insured in the home country for at least 3 months before being posted, 24 months of posting must be followed by a break of at least 2 months before the next, and postings must generally be notified in advance (European Commission). Business trips and postings of up to 3 days will not need prior notification, except in construction (European Parliament summary).
None of this applies yet. The European Parliament adopted the revision on July 7, 2026 and the Council on September 28, 2026, and the act was signed on October 7, 2026 (European Parliament Legislative Observatory). It still has to be published in the Official Journal, and the Your Europe posting page says the new rules apply from 2028. Until then the 1-month rule and the current A1 process stand.
