Tax Residency Rules Expats Get Wrong

February 2026

By Will Glyn

One of the first things people ask when they move abroad is whether they'll still need to pay UK tax. The answer is almost always "it depends" — which isn't particularly satisfying, but it's accurate. Tax residency is one of those areas where assumptions can be costly, and the rules are more nuanced than most people expect.

Over the years, I've seen plenty of expats get caught out by misunderstandings about how residency works. Some discover they're still UK tax resident despite living overseas. Others assume they've escaped the UK tax net entirely, only to find HMRC has a different view. The good news is that most of these mistakes are avoidable — if you know what to look out for.

The 183-day myth

Let's start with the most common misconception: the idea that spending fewer than 183 days in the UK automatically makes you non-resident.

It doesn't.

While 183 days is an important threshold, it's only one part of a much more complex picture. The UK's Statutory Residence Test (SRT), introduced in 2013, uses a combination of factors to determine your status — including how many days you spend in the UK, your ties to the country, and your working patterns.

You could spend just 90 days a year in the UK and still be considered resident if you have enough ties. Equally, you could spend 120 days here and be non-resident if your circumstances support it. The 183-day rule is a simplification that doesn't reflect how the test actually works.

Counting days incorrectly

Even when people understand that days matter, they sometimes count them wrong. Under the SRT, a day spent in the UK is any day when you're present at midnight. Miss your flight and end up staying overnight? That's another day added to your total.

There are some exceptions for transit and unusual circumstances, but the general rule is strict. If you're close to a threshold, keeping a detailed travel diary is essential. HMRC can and does check passport stamps and travel records, so relying on memory isn't a good strategy.

It's also worth noting that the day you leave the UK and the day you return can both count, depending on the timing. If you're regularly flying back and forth, those days add up faster than you might think.

Underestimating UK ties

The SRT doesn't just look at days — it also considers your connections to the UK. These "ties" include things like:

• Having a spouse or partner in the UK
• Having children under 18 in the UK
• Having accessible accommodation in the UK
• Doing substantive work in the UK
• Spending 90 or more days in the UK in either of the previous two tax years

The more ties you have, the fewer days you can spend in the UK before becoming resident. Someone with four ties might become resident after just 45 days. Someone with none might be able to spend up to 182 days without triggering residency.

This is where expats often slip up. Keeping a UK property — even if you don't live in it — counts as a tie. So does having a partner who hasn't moved abroad with you. If your circumstances are borderline, these connections can tip the balance.

Assuming you're automatically non-resident when you leave

Another common mistake is thinking that the moment you board a plane, you stop being UK tax resident. In reality, residency status is determined on a tax-year basis (6 April to 5 April), and the rules don't always work in your favour.

If you leave the UK partway through the tax year, you may be able to claim "split-year treatment," which allows you to be treated as non-resident from your departure date rather than the start of the following tax year. But this isn't automatic — you need to meet specific conditions, and you may need to make a claim.

Without split-year treatment, you could remain UK tax resident for the entire year in which you leave, even if you spent most of it abroad. That can have significant implications for things like capital gains and overseas income.

Forgetting about domicile

Residency and domicile are different concepts, and confusing them is another frequent error. Your domicile is broadly where you consider your permanent home to be — often the country your father was domiciled in when you were born, unless you've actively changed it.

Even if you become non-UK resident, you may still be UK domiciled. And if you are, your worldwide assets could remain within scope for UK inheritance tax. This catches out expats who assume that living abroad for many years means they've severed all tax ties to the UK.

Changing your domicile is possible, but it requires clear evidence of intention to live permanently in another country. Simply moving abroad for work isn't usually enough.

Not keeping proper records

Finally, one of the most practical mistakes is failing to document your position properly. If HMRC ever queries your residency status, the burden of proof is effectively on you. Having clear records of your travel, your ties, and your intentions can make all the difference.

This is especially important in the years immediately after you leave, when your status is most likely to be questioned. Keep copies of flight bookings, rental agreements, utility bills, and anything else that supports your claim to be living abroad.

The bottom line

Tax residency is more complicated than it first appears, and the consequences of getting it wrong can be significant. The 183-day rule is a useful shorthand, but it's not the whole story. What matters is your overall pattern of life — where you spend your time, where your ties are, and where you intend to make your home.

If you're not sure where you stand, it's worth getting clarity sooner rather than later. The rules are technical, but they're not impossible to navigate — and understanding them properly can save you a lot of trouble down the line.

Will is an Independent Financial Adviser with over a decade of experience helping expats make the most of their international status.