Working abroad for a UK employer: PAYE, National Insurance and posting certificates

Your laptop doesn't care where you open it, but two tax offices and two social security systems do. Get both sorted before you go, not after the first payslip.

The short version

• Tax and social security are separate questions. You can stop paying UK income tax and still pay UK National Insurance, or the other way round.
• Your UK employer keeps running PAYE on all your pay until HMRC tells it otherwise. Once you're non-resident, pay for work done abroad generally isn't taxable in the UK, but pay for UK workdays is [1][2][3].
• In the EU, Iceland, Liechtenstein, Norway and Switzerland, a temporary posting of up to two years can keep you in UK National Insurance with a certificate of coverage, often still called an A1 [4][5].
• Countries with a UK social security agreement have their own certificates. Elsewhere, UK National Insurance can continue for the first 52 weeks if certain conditions are met [6].
• The host country usually wants its share of income tax from the day you're living and working there. That's the bit "just working remotely" plans tend to forget.

Two questions, not one

People often say "I'll stay on UK payroll" as if it settles everything. It doesn't. There are two separate tests:

You can be non-resident for UK income tax under the Statutory Residence Test and still have UK National Insurance deducted for two years under a posting certificate. That's normal, and it's the outcome many employers aim for.

Income tax: when does UK PAYE stop?

The default: PAYE carries on

HMRC's guidance to employers is blunt. Keep calculating and deducting PAYE from all pay to employees working abroad, and give the employee a letter showing the departure date, pay to date and tax deducted [1]. HMRC's PAYE manual adds that, without a notification in place, the employer "must operate PAYE on all payments made to the employee for work done both in and outside the UK" [2].

So in month one abroad you'll probably still see full UK tax on your payslip. That's not a mistake by your payroll team.

Getting it changed

There are two ways UK tax on overseas work gets switched off or reduced:

1. You tell HMRC you're leaving. Employees who'll be working abroad full-time for at least a full tax year complete form P85, and HMRC then confirms the tax code your employer should use [1].
2. Your employer notifies HMRC. From 6 April 2025, the old section 690 direction was replaced by a "globally mobile employee" PAYE notification. The employer estimates the split between UK and overseas work and runs PAYE only on the UK share. HMRC can override that estimate with a direction [2][7].

Either way, it's an estimate. You report the actual position on a Self Assessment return with the SA109 residence pages, and you can claim back UK tax deducted on overseas work [2]. HMRC expects an SA record for any employee who works both in and outside the UK [2].

UK workdays stay taxable

If you're non-resident but pop back for a week of meetings in Manchester, those days are UK duties, and UK tax applies to the pay for them. GOV.UK says that for people living abroad who work in the UK, tax is calculated on the days worked in the UK [3]. Keep a diary of UK workdays. HMRC and your future self will both thank you.

The host country's tax

Once you live and work in another country, it usually taxes your salary from the start, whoever pays it. The usual double taxation agreement relief for short business trips doesn't really fit someone who has moved there. The UK's agreement with that country then decides who gets first bite, with relief for any double tax [3].

That can leave your UK employer with obligations of its own over there: registering as an employer, running local payroll, or in some cases creating a taxable presence for the company. This is why HR teams get twitchy about "working from Lisbon for a bit". Raise it early and in writing.

National Insurance and posting certificates

The EU, Iceland, Liechtenstein, Norway and Switzerland

Since Brexit, the UK–EU Trade and Cooperation Agreement covers social security, and all EU member states have opted in to the detached worker rules [4]. If your employer sends you, or agrees for you to work, temporarily in one of these countries for up to two years, you can stay in UK National Insurance and not pay into the local system [4]. Separate conventions cover Iceland, Liechtenstein and Norway, and Switzerland [4].

The proof is a certificate of coverage, which GOV.UK also calls a PDA1. Most people still call it an A1. Your employer deducts UK National Insurance "as if the work had been done in the UK" [1].

How to get one [5]:

1. Your employer is confirmed as eligible by HMRC once, on form CA3821.
2. The employer, the employee or an agent applies online, no more than 12 months before the posting starts.
3. If the posting is longer than the normal limit, attach a signed statement explaining why staying in UK National Insurance is in your interest. Extensions are possible under some agreements, not all.
4. If you'll live there and qualify for UK-funded healthcare, HMRC may also issue an S1.

If you work in the UK and one or more EU countries at the same time, you need a certificate as a multi-state worker [4]. Self-employed people working temporarily in an EU country have their own route, form CA3837 [5]. A certificate of coverage is not a work permit, so you still need the right to live and work there [4].

Countries with a social security agreement

The UK has reciprocal agreements with countries including Canada, India, Japan and the USA [1]. If you're sent temporarily, you may stay in UK National Insurance; your employer applies for the certificate on form CA9107 [1]. Without one, you'll usually pay into the local system instead. GOV.UK's NI38 guidance lists the countries [6].

Everywhere else: the 52-week rule

In countries without an agreement, you keep paying UK National Insurance for the first 52 weeks abroad if all of these apply: you're working abroad temporarily, your employer has a UK place of business, you're ordinarily resident in the UK, and you lived in the UK immediately before starting work abroad [6]. After 52 weeks it stops. The local country may also charge its own contributions, with no agreement to stop double payment.

Voluntary National Insurance

When compulsory UK contributions stop, voluntary contributions can keep your State Pension record ticking over. They don't buy you healthcare in your new country [6]. Our guide to Class 2 and Class 3 contributions explains the options.

A checklist before you go

1. Tell your employer in writing where you'll be and for how long. A "few months in Spain" can quietly become two years.
2. Check the visa or permit that lets you work there. Neither PAYE nor an A1 gives you that right.
3. Ask payroll whether they'll make a globally mobile employee PAYE notification, and file a P85 if you're going for a full tax year.
4. Get the right certificate of coverage or confirm the 52-week rule applies, before you start.
5. Register with the host country's tax office and check whether your employer must run local payroll.
6. Keep a log of UK workdays, and file Self Assessment with the SA109 pages.

A tax adviser who knows both countries can check your situation, especially if equity awards or bonuses span your move. If you'd rather swap notes with people who've done it, our community groups for Brits abroad are full of them.

Sources

1. GOV.UK: Employees working abroad
2. HMRC PAYE Manual PAYE81545: International employments, UK employer's duties
3. GOV.UK: Tax on your UK income if you live abroad
4. GOV.UK: Paying National Insurance if you're going to work in the EU, Gibraltar, Iceland, Liechtenstein, Norway or Switzerland
5. GOV.UK: Apply for a certificate confirming you will pay UK National Insurance when working temporarily abroad (CA3822)
6. GOV.UK: National Insurance if you work abroad
7. HMRC PAYE Manual PAYE81521: Globally mobile employee PAYE notification, HMRC direction

Keep reading

• Leaving the UK: telling HMRC, the P85 and your last tax year
• Split-year treatment: the year you leave
• Voluntary National Insurance from abroad: Class 2 vs Class 3
• Double taxation agreements and reliefs