You have moved from Australia to Britain, or you plan to work here for part of a UK tax year. You may still be an Australian tax resident. UK residence, Australian residence and treaty residence are separate questions.
Start with the UK tax year
HMRC’s guidance on tax residence says residence usually depends on the days spent in the UK during the tax year. The year runs from 6 April to 5 April in the following year.
For the 2025–26 tax year, HMRC gives the dates as 6 April 2025 to 5 April 2026. Your arrival date is assessed within that fixed year. It does not create a separate tax year beginning when you arrive.
HMRC says moving into or out of the UK will usually split the tax year into a non-resident part and a resident part. This is called split-year treatment. It limits UK tax on foreign income to the period when you were living in the UK.
HMRC says you will not receive split-year treatment if you live abroad for less than a full tax year before returning to the UK. Other conditions also apply.
Apply the UK and overseas residence tests
HMRC frames its residence rule as a two-stage test. You must meet one or more UK tests. You must also avoid all automatic overseas tests.
HMRC lists three automatic UK tests:
- You spent 183 or more days in the UK during the tax year.
- Your only home was in the UK for 91 days or more in a row. You must also have visited or stayed in it for at least 30 days during the tax year.
- You worked full-time in the UK for any period of 365 days, with at least one day of that period falling within the tax year being checked.
You may instead be resident under the sufficient ties test. HMRC says this applies where you spend a number of days in the UK and have additional ties, such as work or family. Its wording does not provide one numerical day threshold for this test.
The automatic overseas tests are separate. HMRC says you are usually non-resident if either test applies:
- You spent fewer than 16 days in the UK. The limit is fewer than 46 days if you were not a UK resident for the previous 3 tax years.
- You worked abroad full-time, averaging at least 35 hours a week, and spent fewer than 91 days in the UK. No more than 30 of those UK days may have been spent working.
HMRC says your status can change from one tax year to the next. It advises you to check when your days in the UK change, you buy or sell a UK home, change your job, or have a family, marriage, separation or child-related change.
See what UK residence changes
HMRC’s foreign income overview says non-residents do not pay UK tax on foreign income. UK residents normally pay tax on all their income, whether from the UK or abroad.
Foreign income can include wages from work abroad, foreign dividends and savings interest, rent from overseas property, and income from overseas pensions.
There was an important change on 6 April 2025. Before that date, a person whose permanent home, or domicile, was abroad may not have had to pay UK tax on foreign income. That former non-domicile route is no longer available for foreign income. A person who is UK resident now normally has to consider that income under the changed rule.
Foreign Income and Gains relief may still mean that no UK tax is due. HMRC says eligibility for this relief must be checked separately.
HMRC’s residence guidance also says UK residents pay tax on UK and foreign gains. Non-residents usually pay Capital Gains Tax only on UK property or land, or if they return to the UK.
Work out whether Self Assessment applies
UK tax residence and a Self Assessment return are not interchangeable decisions. HMRC says that, if you need to pay UK tax on foreign income, you usually report it in a Self Assessment tax return.
For the 2025–26 tax year, HMRC gives the following registration rule. You must tell HMRC by 5 October 2026 if you need to complete a return for that year and either:
- you have never sent a tax return before; or
- you were registered before but did not need to send a return for 2024–25.
If neither condition applies, that particular 5 October notification rule does not determine whether you need a return. You must still establish whether your circumstances require one.
HMRC’s Self Assessment deadline guidance sets the following dates:
- A paper return must reach HMRC by 11:59pm on 31 October 2026. It can be sent on or after 6 April 2026.
- An online return must be submitted by 11:59pm on 31 January 2027.
- Self Assessment tax due must be paid by 11:59pm on 31 January 2027.
- If you register after 5 October 2026, HMRC will send a letter or email giving a return deadline three months from the date of that notice. The tax payment deadline remains 31 January 2027.
- HMRC also gives 31 July as the second payments-on-account deadline.
HMRC says to keep records such as bank statements and receipts so the return can be completed correctly. Keep the records for both income and expenses.
Use the treaty as a tie-breaker
HMRC’s text of the 2003 Australia–UK Double Taxation Convention says it applies to people who are residents of one or both countries.
The taxes covered by the Convention include UK income tax, corporation tax and Capital Gains Tax. The Australian taxes listed in the Convention include income tax, resource rent tax for offshore projects, and fringe benefits tax.
The Australian Taxation Office says you can be a tax resident of more than one country at the same time. The treaty tie-breaker is used for dual residents. It can determine your country of residence for treaty purposes and which country has taxing rights over specified classes of income.
Treaty residence is different from residence under each country’s domestic tax rules. The Convention is not a blanket exemption from UK or Australian tax. The ATO also says that citizenship or nationality of another country does not necessarily make you a tax resident under that country’s laws.
If you consider that you are resident in both Australia and the UK, the ATO says you should lodge an early engagement advice request. This assists the ATO in determining your residency status under the relevant agreement.
Check whether Australia still taxes you
The ATO says that, if you remain an Australian tax resident for tax purposes while living overseas, you still need to lodge an Australian tax return.
If you work while living overseas, the ATO says you must declare all foreign employment income. You must also declare any exempt income, even if tax was withheld in the country where you earned it.
An Australian certificate of residency records that, for a stated period, you were an Australian tax resident, were not a temporary resident, and were liable to pay tax on worldwide income in Australia. You may need to provide it to an overseas tax authority.
HMRC says that, if you have not paid tax on foreign income, you may need to apply for a certificate of residence as evidence that you qualify for relief. Do not assume which certificate or relief form applies to your facts. Check with a registered tax adviser before relying on it.
For separate settling-in tasks, see our guides to travel entry documents, a right to work share code, getting an NHS number, the first 30 days in Britain, and planning an Australian family move.
Common questions
Does the date I arrive decide whether I am UK tax resident?
No. HMRC assesses the whole tax year from 6 April to 5 April. Arrival and departure dates are part of the assessment, alongside your home, work and family circumstances.
Does the treaty stop Australia from taxing me?
Not by itself. The ATO says an Australian tax resident living overseas still needs to lodge an Australian return. The treaty can determine treaty residence and taxing rights for specified income, but it does not replace either country’s reporting system.
Does becoming UK tax resident always mean filing a Self Assessment return?
Do not assume that the two decisions are the same. HMRC says a Self Assessment return is usually required for foreign income that must be reported, and it gives a specific 5 October notification rule for the current return period.
Will an Australian certificate prove that I am not UK resident?
No. The ATO certificate records your Australian tax position for a specific period. HMRC may request it as evidence for relief, but it does not replace the UK day-count, home, work and sufficient-ties tests.
Can I always use split-year treatment after moving to the UK?
No. HMRC says it is usually available when you move into or out of the UK, but other conditions apply. It is not available if you have lived abroad for less than a full tax year before returning.