When a US citizen leaves Britain, the UK side ends with a final return for the tax year of departure, and HMRC needs to be told you are going, either on form P85 or on the SA109 residence pages (opens the official HMRC page in a new tab) of a Self Assessment return. If the conditions of a departure case are met, that year is split at the date you leave. The US side does not end at all. Form 1040 covers the whole calendar year, relief for UK tax applies only to the UK part, and any UK accounts you keep stay on your US reports.
This post is for American citizens and green card holders leaving the UK, whether for the US or a third country. It picks up where our guide to US and UK tax returns for Americans in the UK leaves off and mirrors our post on your first UK tax year as an American. It covers telling HMRC, the departure split, the last UK return, US relief in the year you go, and what follows you home.
How do you tell HMRC you are leaving the UK
Which route you use depends on whether you file Self Assessment. Someone who does not usually file a return tells HMRC on form P85, which can also reclaim tax from UK employment. Someone who files Self Assessment reports the departure in the residence section of the return, the SA109 pages, rather than on a P85.
GOV.UK says you must tell HMRC if you leave permanently, go to work full-time abroad for at least a full tax year, or are a foreign national leaving the UK. HMRC's guidance says to send parts 2 and 3 of your P45 with a P85 if you have one, and also says you do not need the form if you are sending a Self Assessment return for the tax year you leave.
For Self Assessment filers, GOV.UK is explicit that HMRC's own online services cannot be used to tell it you are leaving. The SA109 pages go in by post or through commercial software, which our form guide to SA109 explains. Someone going to work full-time abroad for a UK employer for at least a full tax year is the exception: GOV.UK asks for a P85 as well as the return and SA109. Our UK Self Assessment service prepares the departure return and its pages.
- No Self Assessment return for the year: form P85, with parts 2 and 3 of the P45 if you have one
- Self Assessment filer: the residence section of the return, SA109, on paper or through commercial software
- Full-time work abroad for a UK employer for a full tax year: P85 and the return with SA109
- Coming back later: GOV.UK asks you to tell HMRC when you return
When does split-year treatment apply in the year you leave
Only where one of three departure cases fits. Under the Statutory Residence Test (opens the official HMRC page in a new tab), you are resident or non-resident for a whole tax year. Split-year treatment then divides the year of departure into a UK part and an overseas part, and each case has conditions that must all be met.
HMRC's manual sets out Case 1 for someone starting full-time work overseas, Case 2 for the partner who goes with them, and Case 3 for someone who stops having any home in the UK. Each requires UK residence in the year of departure and in the year before, and non-residence in the year after. That last condition is easy to miss: a person who leaves in one tax year and comes back to live in the next generally gets no split.
Case 3 has further tests from the day the last UK home goes. Days spent in the UK for the rest of the year must stay under a strict limit, and within a set period you must become tax resident in another country, spend every night there, or have your only home there. Case 1 needs overseas work meeting a full-time hours test, with limits on UK workdays. Where more than one case fits, priority rules pick the split date. The overseas part starts on the day the UK home ends for Case 3, or on the first day of the qualifying overseas work for Case 1.
- Case 1: you start full-time work overseas and meet the overseas work criteria
- Case 2: your partner falls within Case 1 and you leave to live with them abroad
- Case 3: you stop having any UK home and meet the day limit and the overseas connection test
What goes on your final Self Assessment return
The return for the tax year of departure reports your worldwide income for the UK part of the year and only UK income for the overseas part, if the year is split. The split-year case and the departure date go on SA109.
The deadlines are the ordinary Self Assessment deadlines (opens the official GOV.UK page in a new tab): 31 October for a paper return and 31 January for an online return, after the end of the tax year of departure. Because SA109 cannot go through HMRC's free online service, an online filing needs commercial software. The same 31 January date applies to any balance of UK tax.
Leaving does not end UK tax on UK income. A non-resident who keeps a let flat stays within the rules for rental income of people living abroad (opens the official GOV.UK page in a new tab), and a sale of UK residential property after you leave is reported under the rules for non-residents selling UK property (opens the official HMRC page in a new tab), generally within 60 days of completion. HMRC's residence guidance also has temporary non-residence rules: someone who was UK resident for most of the tax years before leaving and returns within a short period set by the rules can be taxed on return on certain gains and income received while away.
Can you claim the foreign earned income exclusion in the year you leave
Yes, for the part of the year you qualify, if you meet a test. The foreign earned income exclusion (opens the official IRS page in a new tab) covers pay for work done abroad during a qualifying period. In the year you leave, that period ends with your departure, and the annual maximum is prorated by the qualifying days in the year.
The bona fide residence test is the natural fit for someone who has lived in the UK for several years. The IRS says that once residence has been established for an uninterrupted period including a full tax year, it covers partial years at either end, ending when you give up the foreign residence. Someone who leaves in the middle of their second year abroad may not have a full year to rely on.
The physical presence test asks for 330 full days in a foreign country within any period of twelve consecutive months, and the IRS lets you choose the period that gives the largest exclusion. For a departure year, that usually means a period ending around the day you leave. Publication 54 (opens the official IRS page in a new tab) says the maximum is prorated by the days you met either test in the year, so the $130,000 limit for 2025 shrinks to a fraction. Pay for work done in the US after you return is US income and cannot be excluded. The claim goes on Form 2555.
How the foreign tax credit works for UK tax in the departure year
UK tax on the UK part of the year can be credited against the US tax on the same income. The foreign tax credit (opens the official IRS page in a new tab) needs no qualifying test, so it works even where the exclusion does not.
The difficulty is timing. The UK tax year of departure straddles two calendar years, and its final liability may not be known until the last return is done. Publication 514 (opens the official IRS page in a new tab) lets you claim UK tax in the year it is paid or, by election, the year it accrues, and unused credit carries back one year and forward ten. Our post on paid or accrued credit timing explains the choice. Publication 514 treats a refund of foreign tax as a redetermination, and where it changes your US tax you generally file Form 1040-X.
Take a US citizen employed in Edinburgh who has lived in the UK for several years and leaves in late summer for a job in Chicago, giving up her rented flat when she goes. Her UK year may split under Case 1 or Case 3 if she stays non-resident the following year. Her Form 1040 reports the Edinburgh salary and the Chicago salary. She can credit the PAYE deducted from the Edinburgh pay on Form 1116, or exclude that pay for her bona fide residence days. A P85 or final return that produces a UK refund reduces the credit.
What follows you back to the United States
Several US settings change. You may become a resident of a state again, the deadlines and Form 8938 thresholds for people abroad may stop applying, and UK accounts you keep remain reportable.
State residence starts under the new state's own rules, usually with a part-year resident return for the year you arrive. Our post on leaving California or New York for London shows how strictly some states define residence, and our multi-state tax filing service prepares the state return with the federal one. The automatic extension to 15 June (opens the official IRS page in a new tab) applies only if you live and work outside the US on the regular due date, so a return for the departure year filed after you are home is due by 15 April.
GOV.UK confirms an ISA (opens the official GOV.UK page in a new tab) can stay open after you leave, but you cannot pay into it while non-resident. The US still taxes its income and gains, and funds inside it are commonly PFICs, as our post on why a stocks and shares ISA worries the IRS explains. A UK pension stays on the FBAR (opens the official FinCEN page in a new tab), as our post on whether a UK pension is reportable on the FBAR covers. For Form 8938, the higher abroad thresholds need a presence test met in a period ending in the year; after that, the lower figure of $50,000 at year end or $75,000 at any time applies to a single filer living in the US.
Our individual tax returns service prepares the final UK return and the departure-year Form 1040 from one set of figures, so the split date, the credit and the account list agree. For the wider picture of filing in both countries, return to the guide to US and UK tax returns for Americans in the UK.
- FBAR on all foreign accounts once the aggregate exceeds $10,000, due 15 April, extended automatically to 15 October
- Form 8938 at the US thresholds once you no longer meet a presence abroad test
- ISA income and gains on Form 1040 every year, with Form 8621 for funds where required
- UK pension statements kept for the FBAR and for the US position on later withdrawals
General information, not advice. The right answer depends on your circumstances and the tax year concerned.
