The UK Self-Assessment Tax Return for Expats and Non-Residents: A Complete Guide

Living abroad does not eliminate all UK tax obligations. Non-UK residents with UK income or UK assets face a range of reporting requirements under the UK self-assessment system, and the consequences of non-compliance — penalties, interest, and in serious cases criminal prosecution — are substantial.

This guide is designed for internationally mobile individuals: British expats living overseas, foreign nationals who have left the UK, and anyone with UK assets generating income or gains whilst resident elsewhere.

Who Must File a UK Self-Assessment Return?

A non-UK resident is required to file a UK self-assessment (SA) tax return if they have:

UK rental income: Any income from letting UK property must be reported on a UK tax return, regardless of the amount. Even if you are a Non-Resident Landlord (NRL) with tax deducted at source by your letting agent, an annual return is generally required to reconcile the tax withheld against the actual liability after allowable expenses.

UK employment income not fully taxed at source: If you have income from UK employment that is not taxed under PAYE, or where the PAYE code is incorrect, a return is needed to report and settle the liability.

UK trading income: Income from a UK business operated as a sole trader, or as a partner in a UK partnership.

UK pension income: State pension and most occupational/private pensions are paid gross (no tax deducted) or under a PAYE code. If the total UK income exceeds the personal allowance (note: non-residents may not be entitled to the UK personal allowance — see below), a return is required.

UK dividends and interest: If you have UK-source dividends or bank interest above the relevant savings/dividend allowances, these may need to be reported.

UK capital gains: Disposing of any UK residential or commercial property as a non-resident triggers the Non-Resident CGT (NRCGT) reporting requirement — a separate 60-day return — as well as inclusion in the annual SA return if one is required.

High income (over £100,000 from UK sources): Where UK-source income exceeds £100,000, the personal allowance tapers to nil and an SA return is required regardless of other factors.

The Non-Resident Landlord Scheme

The Non-Resident Landlord (NRL) scheme applies to non-UK resident individuals, companies, and trustees who receive UK rental income. Under the scheme:

• The letting agent (or the tenant, if there is no agent and the rent exceeds £100/week) deducts basic rate income tax (currently 20%) from the rental income before paying it over
• The landlord receives rental income net of tax
• An annual SA return is then filed to report the rental income, claim allowable expenses (mortgage interest at the basic rate, repairs, management fees, insurance, ground rent), and either pay any additional tax due (where the effective rate exceeds 20%) or reclaim any overpayment

Non-resident landlords can apply to HMRC to receive rental income gross (without deduction at source) — useful where the rental profit after expenses is low or nil. This requires an application via form NRL1 and HMRC approval.

The Personal Allowance for Non-Residents

Non-UK residents are not automatically entitled to the UK personal allowance (£12,570 for 2026/27, frozen at this level). They are entitled to it only if they are:

• British citizens
• Citizens of an EEA country (though post-Brexit arrangements vary)
• Residents of a country with a Double Tax Agreement that specifically grants the UK personal allowance (many UK DTAs include this provision — check the specific DTA for your country of residence)

If you are not entitled to the personal allowance, UK tax is payable on every pound of UK-source income.

The SA109: The Key Supplementary Page for Non-Residents

The SA109 ("Residence, remittance basis and domicile") is the supplementary page of the UK self-assessment return that non-resident and non-domiciled individuals must complete. It is not available within HMRC's basic free filing software — a more capable system or professional preparation is required.

The SA109 requires you to state:

• Your UK residence status for the year (UK resident / not UK resident / split year treatment)
• The basis for your residence determination under the Statutory Residence Test (SRT)
• Whether you are claiming split-year treatment (if you arrived or departed the UK mid-year)
• Whether you are claiming the Foreign Income and Gains (FIG) regime (new from April 2025)
• Remittance basis elections (for pre-April 2025 tax years, if applicable)
• Non-domicile status and basis of claim

The SA109 is technically the most complex part of the non-resident UK tax return. Determining your SRT status correctly — particularly in a split year or where there are multiple ties — requires careful analysis of all relevant facts.

The 60-Day NRCGT Return: A Separate Obligation

If you sell UK residential or commercial property as a non-resident, you are required to file a Non-Resident CGT (NRCGT) return within 60 days of completion, regardless of whether you are otherwise required to file an annual SA return.

The NRCGT return must be filed even if:

• The gain is nil or negative (a loss)
• Private Residence Relief eliminates the entire gain
• You are within a Double Tax Agreement that exempts the gain from UK tax

Failure to file within 60 days triggers an automatic penalty of £100, rising to £300 after 6 months. HMRC has been actively issuing penalties for late NRCGT returns.

If you are also required to file an annual SA return, the property disposal is included there too — but the 60-day return is still required separately.

Key SA Deadlines

Event	Deadline
Paper SA return filing	31 October following the tax year end (e.g., 31 October 2025 for 2024/25)
Online SA return filing	31 January following the tax year end (e.g., 31 January 2026 for 2024/25)
Tax payment (balancing payment)	31 January following the tax year end
First payment on account (if applicable)	31 January following the tax year end
Second payment on account	31 July following the tax year end

Payments on account apply where the SA tax liability exceeds £1,000 and less than 80% of the liability was collected at source (PAYE, NRL deductions). Each payment on account is 50% of the prior year's tax liability, due on 31 January and 31 July.

For non-residents who sell UK property and pay CGT via the 60-day return, those payments reduce the balancing payment due in January.

Double Taxation and Credit Relief

If you are resident in another country and also have UK-source income, you may face a risk of double taxation — paying tax in both the UK and your country of residence on the same income. Double Tax Agreements (DTAs) between the UK and most countries resolve this by:

• Allocating taxing rights to one country (e.g., UK property income: taxing rights in the UK)
• Requiring the other country to provide a credit for the tax paid (e.g., your country of residence credits the UK income tax paid)

When filing both your UK SA return and your overseas return, ensure you:

• Obtain evidence of UK tax paid (HMRC will issue a "Notice of Coding" or SA payment record — keep these)
• Claim the appropriate foreign tax credit on your overseas return
• Check whether your DTA provides for exemption (no UK tax) or credit relief (UK tax paid, overseas credit)

HMRC's Offshore Disclosure Activity

HMRC has significantly increased its offshore disclosure and compliance activity, using data shared under the Common Reporting Standard (CRS) and information from overseas tax authorities. Rental income, capital gains, and investment income in UK accounts are all reported to HMRC.

If you have unfiled UK returns, HMRC's Worldwide Disclosure Facility (WDF) allows voluntary disclosure with reduced penalties compared to a formal investigation. Taking professional advice on the disclosure route is strongly recommended.

Compliance Caveats

UK tax law changes frequently. The rules described in this article reflect the position as of mid-2026 and may have changed. This article is for general information only and does not constitute tax advice. Non-resident tax compliance in the UK is technically demanding and individual circumstances vary significantly. Professional advice from a qualified UK tax adviser or accountant is strongly recommended. Penalties for late or incorrect returns can be substantial.

How Global Investments Can Help

Global Investments works with internationally mobile HNW individuals on cross-border tax planning and compliance. Our network includes specialist UK tax advisers with experience in non-resident landlord returns, NRCGT reporting, SA109 completion, and HMRC disclosure. If you are unsure of your UK filing obligations — or know you have unmet obligations — contact us to discuss the appropriate course of action.