U.S. Expat Taxes in the UK

Working or retiring in the United Kingdom can introduce a different tax year, unfamiliar savings accounts, and pension decisions that affect your U.S. return.

Valoria helps U.S. taxpayers identify filing requirements and address the cross-border details that a routine domestic return may miss.

U.S. citizens generally remain subject to tax on worldwide income. A UK salary or a second passport does not automatically remove the requirement to file a U.S. return. Filing depends on the applicable income thresholds and other rules.^[1]

If you hold a green card or have recently changed your immigration status, confirm your U.S. tax status rather than assuming the move ended it.

The United States generally uses the calendar year for individual returns. The UK tax year runs from April 6 to April 5. UK residency is assessed under its own rules, including the Statutory Residence Test.^{[10, 15, 16]}

Keep monthly payroll records as well as your P60 and any P45. Preparing a U.S. calendar-year return often requires records spanning portions of two UK tax years. This also makes the timing of foreign tax credits worth reviewing.

Where Self Assessment applies, the standard UK deadlines are October 31 for paper returns and January 31 following the tax year for online returns and the balancing payment. Other payments, registration deadlines, and exceptions may apply.^[16]

Qualifying UK income taxes may support a Foreign Tax Credit against U.S. tax, subject to the relevant limitations. Income sourcing, separate income categories, and tax-payment timing affect the calculation.^[3]

The Foreign Earned Income Exclusion may apply to qualifying employment or self-employment income. The 2026 maximum is $132,900 per qualifying person, with eligibility and proration rules. It is not a general exemption for everything earned or received abroad.^[4]

These choices should be compared in the context of the whole return. Neither a higher UK tax rate nor a treaty automatically guarantees a zero U.S. balance.

The UK generally exempts ISA interest and investment income or gains from UK tax. That UK exemption does not establish a corresponding U.S. exemption. U.S. worldwide-income rules still require consideration.^{[1, 17]}

Review the actual holdings. Non-U.S. pooled funds inside a stocks and shares ISA may create PFIC issues and Form 8621 obligations. An account’s label does not resolve the treatment of every asset it contains.^[9]

Planning point: Have the U.S. consequences reviewed before making significant new investments or restructuring an existing portfolio.

Workplace pensions, SIPPs, and other arrangements should be reviewed separately. Contributions, investment growth, distributions, transfers, and reporting can raise different questions. The U.S.–UK treaty may affect the outcome, but relief depends on the facts and relevant provisions.^{[18, 19]}

Before taking a lump sum or transferring a pension, provide the plan documents, contribution history, and proposed transaction details. Do not assume a transaction described as tax-free in the UK is automatically tax-free in the United States.

On April 6, 2025, the four-year foreign income and gains, or FIG, regime replaced the remittance basis. Qualifying new residents generally need ten consecutive prior tax years of non-UK residence, and relief must be claimed within the applicable first four residence years. Claiming relief can also mean losing certain UK allowances.^[20]

For an American, reduced UK tax may leave less foreign tax available for a U.S. credit. Model the combined result before treating a UK tax saving as the final answer.^{[3, 20]}

UK accounts may trigger FBAR reporting when the aggregate foreign-account threshold is met. Form 8938 is separate and may also apply. The scope and thresholds differ, so neither disclosure should be used as a substitute for checking the other.^[6]

If you own a UK limited company, operate a business, or hold interests through another entity, flag that at intake. Foreign business interests may require additional U.S. information returns.^[10]

The U.S.–UK social security agreement can help determine applicable coverage for employment or self-employment. Keep any certificate of coverage supporting the position taken.^[11]

The regular individual deadline is generally April 15. Qualifying taxpayers abroad generally receive until June 15, with the required statement; a further timely extension can generally move filing to October 15. Interest still runs on unpaid tax from the regular April deadline.^[12]

Track the UK and U.S. dates separately, and confirm the rules for the relevant year.

An eligible non-willful taxpayer may qualify for the Streamlined Foreign Offshore Procedures. These generally involve three qualifying return years, six FBAR years, and a signed explanation of non-willfulness. Qualification, tax, interest, and the completeness of the submission all need review.^[14]

• Prior U.S. returns and UK Self Assessment returns, if filed.
• P60s, P45s, monthly payslips, and UK tax-payment records.
• Bank and investment statements, including ISA holdings.
• Pension and SIPP documents, contributions, and withdrawals.
• Company ownership details, rental records, and property transactions.
• Travel dates, missed filing years, and tax-authority correspondence.