A1 Certificates Explained: What They Are and Why Clients Are Requesting Them

A1 Certificates: What Freelancers Need to Know 

If you work on projects in Europe, you may have noticed that more clients are requesting an A1 certificate before mobilisation, particularly where work is carried out onshore, nearshore, within territorial waters (12 nautical miles), or across multiple EU/EEA jurisdictions. This request has become increasingly common as companies strengthen their compliance procedures for cross-border work. 

While the requirement may appear administrative, the A1 certificate is an important document that confirms which country’s social security system applies to you while working abroad.  

 

What is an A1 Certificate? 

An A1 certificate is an official document that confirms you remain covered by the social security system of your home country while temporarily working in another EU/EEA country, the UK/Switzerland, or on a vessel sailing under another country’s flag. 

Its main purpose is to ensure you do not pay social security contributions in more than one country for the same work. 

Without a valid A1 certificate, local authorities may apply host-country social security contributions, which can lead to unexpected costs and, in some cases, backdated liabilities for both the individual and the wider supply chain. 

It is also important to note that an A1 certificate does not replace visa or work permit requirements, and it does not remove local tax obligations. A1 certificates are typically only available to individuals covered under EU/EEA/UK social security systems and must be assessed on a case-by-case basis. 

 

When You May Need an A1 Certificate 

You may be asked to provide an A1 certificate if you are: 

• Working on projects located in the EU, EEA, Switzerland, or the UK (either offshore or onshore) 

• Mobilising to a vessel sailing under the flag of an EU, EEA, Swiss, or UK-registered vessel 

• Carrying out assignments across multiple EU, EEA, Swiss, or UK jurisdictions during the year 

In many cases, the requirement is determined by local labour regulations or client compliance policies, rather than the length of the assignment. Some European countries expect workers to hold an A1 certificate even for short visits or brief work activities. 

 

Situations Where an A1 May Not Be Required 

There are also circumstances where an A1 certificate may not be necessary, for example: 

• Work that takes place entirely outside Europe/the EEA 

• Assignments in countries that do not participate in the EU/EEA social security coordination framework 

• Certain short-notice mobilisations where retrospective applications are permitted  

• Mobilisations with a duration of less than 2 weeks 

However, because enforcement practices differ between countries and clients, many freelancers choose to apply for an A1 certificate in advance to avoid delays. 

 

Validity and Application 

Applying for an A1 certificate is generally free of charge and is done through the social security authority in your country of residence. 

Key points to note: 

• Certificates are usually issued for the duration of the assignment, typically up to 24 months. 

• Applications should ideally be submitted before travelling or mobilising. 

• In some situations, retrospective applications may be possible if travel occurs at short notice. 

Processing times can vary, so applying early can help avoid delays during mobilisation. 

 

Please find below a list of contact details/addresses of institutions responsible for issuing the portable A1 document: 

https://drive.google.com/file/d/1T7qi9xx-Ra45k9i2w92Z3qXLH8kzB6eJ/view

 

Why Clients Request the Certificate 

Across Europe, labour inspectors may request documentation confirming where a worker’s social security contributions are being paid. If the appropriate documentation is not available, companies can face penalties or requests for additional contributions. 

For this reason, many clients now require contractors to provide an A1 certificate before starting work. 

Depending on the project, clients may request: 

• A valid A1 certificate prior to mobilisation, or 

• Proof that an application has been submitted 

Your Precise Consultants Account Manager will inform you if an A1 certificate is required for a specific assignment. 

 

Working Outside Europe 

If you are working outside Europe, an A1 certificate will not apply. Instead, similar documentation may be required under bilateral social security agreements. 

The most common equivalent is a Certificate of Coverage (CoC), which confirms which country’s social security system applies when working between countries such as: 

• United Kingdom and United States 

• United Kingdom and Canada 

• United Kingdom and Japan 

• United Kingdom and Australia 

Although the document name may differ, the purpose is the same: to confirm where social security contributions should be paid and to avoid double contributions. 

 

Practical Tip 

If you frequently work on assignments in Europe/EEA countries or on EU-flagged vessels, it can be helpful to ensure you have an A1 certificate available before mobilisation. Having the document ready can help avoid last-minute delays if a client requests it as part of their compliance process. 

From a Precise perspective, we generally recommend that freelancers apply for an A1 certificate for assignments exceeding four weeks in duration — particularly where the assignment is likely to extend beyond this or where you expect to be working regularly within European waters. 

More broadly, our approach is guided by the level of compliance exposure involved. Where an individual is entering a local tax system, is likely to be subject to local tax deductions, requires a work permit, where client requirements are more stringent, or in countries where A1 compliance is known to be actively audited, we take a firmer position on ensuring that an A1 certificate is in place prior to mobilisation. 

That said, requirements and interpretations can vary depending on the jurisdiction, client, and project specifics, and there may be differing views on how strictly this should be applied in certain scenarios. As such, each case should be assessed individually to ensure the most appropriate and compliant approach. 

 

* Disclaimer: Nothing in this article constitutes legal advice. Specialist legal advice should be taken in relation to specific circumstances. The contents of this article are for general information purposes only. Whilst we endeavour to ensure that the information is correct, no warranty, express or implied, is given as to its accuracy and we do not accept any liability for error or omission.