Do I Need to File a UK Tax Return? 2025/26 Guide

Key points

Most people taxed only through PAYE never file. Expats and non-residents usually do, because a residence change needs a return to claim the right treatment.

✓ Non-residents with UK rental income must file, even if the letting agent pays the rent gross.

✓ Non-residents whose only UK income is bank interest or dividends usually do not need a return unless HMRC asks.

✓ HMRC's free online service cannot file the SA109 residence pages, so non-residents and split year claimants file on paper or use commercial software.

✓ For 2025/26, register by 5 October 2026 if you are new to Self Assessment. File on paper by 31 October 2026, or online by 31 January 2027.

✓ If HMRC sends you a notice to file, you must file by the deadline, even if you owe nothing.

Most people in the UK never file a tax return. PAYE takes the right tax from wages and pensions, and that is the end of it. Self Assessment exists for everything PAYE cannot reach: self-employment, rent, gains, foreign income, and the tax consequences of moving into or out of the UK.

This guide covers the 2025/26 tax year (6 April 2025 to 5 April 2026). The return is due online by 31 January 2027. If you have never filed before and need to, you must register with HMRC by 5 October 2026.

HMRC will not always know your circumstances have changed. Working out whether you need to file is your responsibility, not theirs.

What is a Self Assessment tax return?

A tax return reports income and gains that have not already been taxed correctly at source, claims any reliefs you are entitled to, and calculates the balance you owe or the refund you are due.

The main return is the SA100. You add supplementary pages for the income you have, such as SA103 for self-employment, SA105 for UK property, SA106 for foreign income, SA108 for capital gains and SA109 for residence. The last one matters for anyone who has moved into or out of the UK.

One rule overrides everything else in this guide. If HMRC sends you a notice to file, you must file by the deadline on the notice, even if you owe nothing. If you think you should not be in the system, ask HMRC to withdraw the notice rather than ignoring it.

👉 HMRC guidance: Self Assessment tax returns

👉 The law: Taxes Management Act 1970, section 8 (personal return)

Filing triggers for expats and non-residents

So many internationally mobile people end up in Self Assessment because residence changes almost always need a return to claim the right treatment, and HMRC's PAYE system cannot do it for you.

Image 1: the common filing triggers

If you are UK resident

➜ Foreign income or gains. Since 6 April 2025 the remittance basis has gone, so UK residents are taxed on foreign income and gains as they arise. That income goes on the return, with credit for foreign tax.

➜ The FIG regime. New arrivals who were non-resident for 10 consecutive years can claim four years of relief on foreign income and gains, but only through the return. See our guide to the 📖 4-year FIG regime.

➜ The Temporary Repatriation Facility. Former remittance basis users designate old offshore income and gains on the return. See our guide to the 📖 Temporary Repatriation Facility.

➜ Arriving part-way through the year. Split-year treatment has to be claimed on the SA109 residence pages.

➜ Returning within five years. Coming back after a short period abroad can bring gains and some income from the non-resident years into charge. See our guide to the 📖 temporary non-residence rules.

If you are non-resident

➜ UK rental income. You must file even if your letting agent pays you gross under the non-resident landlord scheme. Gross payment only defers the tax to the return. See our guide to the 📖 non-resident landlord scheme.

➜ Leaving part-way through the year. Most leavers are owed a refund of PAYE, and split-year treatment is claimed on the SA109. See our guide to 📖 split-year treatment.

➜ UK workdays. Salary for work physically done in the UK stays taxable here. See 📖 working remotely abroad for a UK company.

➜ Selling UK property. Non-residents must report every disposal of UK land or property within 60 days, even where no tax is due, and include it on the return if they file one. See our guide to 📖 non-resident capital gains tax.

If your only UK income as a non-resident is bank interest or dividends, that income is usually disregarded income, which caps your UK tax on it, and you will not normally need a return for it alone unless HMRC asks. See our guide to 📖 disregarded income and our overview of 📖 what the UK taxes once you have left.

👉 HMRC guidance: Tax on your UK income if you live abroad

👉 The law: Income Tax Act 2007, section 811 (limit on liability of non-residents)

Who must file a UK tax return?

For 2025/26, you need a return if any of the following applied in the tax year:

➜ Self-employment: you were a sole trader with gross income over £1,000, before expenses.

➜ Partnerships: you were a partner in a business partnership.

➜ Capital Gains Tax: you had CGT to pay, and did not report it through HMRC's real-time CGT service.

➜ High Income Child Benefit Charge: you owe the charge and do not pay it through your tax code.

➜ Off-payroll work: you are an off-payroll worker repaying a student or postgraduate loan.

You will also usually need a return if you had untaxed income that cannot be collected another way. In practice that means:

➜ Rental income: from UK or overseas property, after the £1,000 property allowance.

➜ Untaxed income of £2,500 or more: such as tips, commission or casual work paid gross.

➜ Dividends over £10,000: smaller amounts above your allowances can usually go through your tax code instead.

➜ Pension annual allowance charge: if contributions exceeded your allowance, the charge is reported on a return.

➜ Employment expenses over £2,500: claims above this level go through Self Assessment rather than a simple claim.

👉 HMRC guidance: Who must send a tax return

👉 The law: Taxes Management Act 1970, section 7 (notice of liability to tax)

When you do not need to file

Several recent changes mean fewer people need a return than before:

➜ High earners taxed only through PAYE. The old rule that PAYE earners over £100,000, and later £150,000, had to file was removed from 2024/25. If all your income is taxed through PAYE and nothing else on this page applies, you do not need a return.

➜ High Income Child Benefit Charge. Since autumn 2025, employed people whose only reason for filing is the charge can leave Self Assessment and pay it through their tax code instead.

➜ Small amounts of untaxed income. Below £2,500, HMRC can usually collect the tax through your tax code. Tell HMRC between the end of the tax year and 5 October.

➜ Gains, if you are UK resident. The real-time CGT service lets you report and pay without registering for Self Assessment.

If you are already registered and no longer need to file, tell HMRC. Until you do, they will keep issuing notices, and late filing penalties follow each one.

👉 HMRC guidance: If you no longer need to send a tax return

👉 The law: Taxes Management Act 1970, section 8B (withdrawal of notice to file)

How to register for Self Assessment

You register with HMRC by 5 October after the end of the tax year in which you first needed to file.

For example, if you started letting a flat in May 2025, that income falls in the 2025/26 tax year, so you must register by 5 October 2026. HMRC then issues your Unique Taxpayer Reference (UTR), a ten-digit number that stays with you for life. The activation letter goes by post, so leave time if you are overseas.

Register late and you may face a failure to notify penalty if the tax is not paid by 31 January. It is based on the tax left unpaid, so registering on time matters most when there is tax to pay.

👉 HMRC guidance: Register for Self Assessment

👉 The law: Finance Act 2008, Schedule 41 (failure to notify penalties)

Non-residents without a UK address or National Insurance number often struggle with online registration. Our guide to 📖 HMRC forms for expats covers the paper route.

Self Assessment deadlines for 2025/26

The UK tax year runs from 6 April to 5 April. For the 2025/26 year, the key dates are:

Image 2: 2025/26 deadlines and what lateness costs

➜ 5 October 2026: register for Self Assessment if you are filing for the first time.

➜ 31 October 2026: file a paper return.

➜ 30 December 2026: file online by this date if you owe less than £3,000 and want it collected through your tax code.

➜ 31 January 2027: file online, and pay the balance for 2025/26 plus your first payment on account for 2026/27.

➜ 31 July 2027: pay your second payment on account.

Worked example: The first-year bill

Payments on account catch out most new filers. If your bill is over £1,000 and less than 80% of your tax was collected at source, HMRC asks for two advance payments towards next year, each half of this year's bill. Sam starts letting a flat in 2025/26 and owes £4,000 on the rental profit.

That is £6,000 due in January rather than the £4,000 Sam expected. If income is falling, you can apply to reduce payments on account, but interest applies if you reduce them too far.

👉 HMRC guidance: Understand your Self Assessment tax bill

👉 The law: Taxes Management Act 1970, section 59A (payments on account)

What happens if you file or pay late?

Late filing penalties are automatic and apply even if you owe no tax at all:

➜ 1 day late: a £100 penalty.

➜ 3 months late: £10 a day for up to 90 days, a maximum of £900.

➜ 6 months late: 5% of the tax due or £300, whichever is greater.

➜ 12 months late: another 5% or £300, whichever is greater.

Paying late is charged separately: 5% of the unpaid tax at 30 days, 6 months and 12 months. Interest runs on top from the day after the due date, at the Bank of England base rate plus 4%.

If you had a reasonable excuse, such as serious illness, you can appeal. It is far easier to file on time and agree a payment plan if you cannot pay in full.

👉 HMRC guidance: Self Assessment penalties

👉 The law: Finance Act 2009, Schedule 55 (late filing penalties)

Making Tax Digital: what changed from April 2026

From 6 April 2026, sole traders and landlords must keep digital records and send HMRC quarterly updates if their qualifying income is over the threshold. Qualifying income is gross self-employment and property income before expenses:

➜ From April 2026: qualifying income over £50,000 on your 2024/25 return.

➜ From April 2027: over £30,000 on your 2025/26 return.

➜ From April 2028: over £20,000.

You still finalise the year after it ends, and other income such as salary, dividends and gains goes into that year-end submission. For jointly owned property, only your share of the rent counts towards the threshold.

Non-residents get breathing space. If you filed the SA109 residence pages for 2024/25 and expect to file them for 2026/27, you are automatically exempt until April 2027 at the earliest. Anyone without a National Insurance number is exempt too.

👉 HMRC guidance: Exemptions from Making Tax Digital for Income Tax

How to file your tax return

If your affairs are straightforward, HMRC's free online service works well. You sign in through your personal tax account or Government Gateway.

There is one significant gap. HMRC's online service cannot file the SA109 residence pages, which every non-resident and every split-year claimant needs. You can either file the whole return on paper, with the earlier 31 October deadline, or buy commercial software that supports SA109 and file online by 31 January. You cannot mix the two. The third option is to have an adviser file it for you, which is what our UK tax return service for expats is for.

👉 HMRC guidance: File your Self Assessment tax return online

👉 HMRC list: Self Assessment commercial software suppliers

Keep your records. HMRC expects you to keep them for at least 22 months after the end of the tax year, or 5 years after the 31 January deadline if you are self-employed or a landlord. For cross-border returns, that includes travel records supporting your residence position.

Frequently asked questions

Do I need to file a UK tax return if I live abroad?

Often, yes. It depends on your UK income, not on where you live. You usually need to file if you have UK rental income, UK self-employment income or a UK pension that is not fully taxed, if you are reclaiming overpaid UK tax, or if you are claiming split-year treatment or non-resident status. Non-residents file the SA109 residence pages, which HMRC's own free online service does not support.

Do I need to file a tax return if I am only employed?

Usually not. If all your income is taxed through PAYE, you do not need a return, whatever you earn. You will still need one if you have other untaxed income, gains to report, or HMRC sends you a notice to file.

What is the deadline to register for Self Assessment for 2025/26?

5 October 2026. You need to register by then if you are filing for the first time, or if you did not need to file for 2024/25. HMRC will then send you a Unique Taxpayer Reference.

Do I have to file if I do not owe any tax?

Yes, if HMRC has sent you a notice to file. The £100 late filing penalty applies even when no tax is due. If you no longer need to be in Self Assessment, ask HMRC to withdraw the notice instead.

Can I file the SA109 residence pages online with HMRC?

No. HMRC's free online service does not support SA109. Non-residents and split-year claimants either file a paper return by 31 October or use commercial software to file online by 31 January.

Last reviewed on 22 October 2026 by Emma McDermott, ATT, founder of Global Tax Consulting, in line with the law in force at that date: Taxes Management Act 1970, section 8 and Taxes Management Act 1970, section 7, and the HMRC guidance cited above.