US Expat Tax Deadline Calendar 2026

Most Americans living abroad have until June 15, 2026 to file their 2025 federal return — an automatic two-month extension that requires no form, only a statement attached to the return. Any tax owed still accrues interest from April 15, 2026. The FBAR is due April 15, with an automatic extension to October 15, 2026.

An American living outside of the U.S. files on three different calendars:

• The U.S. federal clock sets four key dates between April and December
• The FBAR keeps a separate schedule of reporting dates
• The country you reside in opens and closes its filing season on its own dates

This page puts every 2026 date in one place, in order, with the rules behind each one. Meeting three sets of filing dates is complex, and the work of coordinating them and keeping each date met can be placed with a suitably experienced professional appointed for that purpose.

The federal clock: April, June, October, December

April 15, 2026 is the anchor. It is the due date of the 2025 return for a calendar-year filer, and — more importantly for anyone using an extension — it is the day the meter starts. Publication 54 states the rule plainly: even where an extension applies, interest runs on any tax not paid by the regular due date. Every later date in the federal column extends the paperwork, never the payment.

June 15, 2026 is the automatic two-month extension. It belongs to citizens and resident aliens who, on the regular due date, are living outside the United States and Puerto Rico with their main place of business also outside, and to those on military or naval duty abroad. Nothing is filed in advance to claim it — the return simply arrives by June 15 with a statement attached explaining which situation applied.

October 15, 2026 requires a form. Form 4868, filed before the automatic two-month extension date runs out, moves the filing deadline to mid-October; filers abroad check the box on line 8 identifying themselves as out of the country. The form asks for an accurate estimate of the tax due, because what it extends is filing time only.

December 15, 2026 is the last rung, and the only discretionary one. A taxpayer abroad who cannot meet the October date writes the IRS a letter explaining why two further months are needed, and sends it by October 15. Publication 54 frames this additional two-month extension as a request, not an entitlement — it is asked for, never assumed.

The FBAR runs on its own track

FinCEN Form 114 — the Report of Foreign Bank and Financial Accounts — is due April 15, 2026 for accounts held during 2025, and it never touches the tax return. It is filed electronically through FinCEN’s BSA E-Filing System and goes to the Treasury, not the IRS. The obligation attaches to any US person whose foreign financial accounts, taken together, exceeded $10,000 at any time during the calendar year — a threshold measured on the aggregate, not per account.

The extension is the part most often misread. FinCEN grants every filer who misses April 15 an automatic extension to October 15, 2026, and its due-date announcement states that specific requests for the extension are not required. There is no FBAR extension form, and filing Form 4868 has no effect on it — the two deadlines merely happen to share a day in October.

Form 8938 travels with the return

The FATCA counterpart, Form 8938, has no deadline of its own — it must be attached to the annual income tax return, so it is due whenever that return is due, extensions included. A filer using the June 15 abroad extension attaches it in June; a filer on Form 4868 attaches it in October. The thresholds are higher abroad: for taxpayers living outside the United States, the form applies where specified foreign financial assets exceed $200,000 on the last day of the year or $300,000 at any time during it — $400,000 and $600,000 on a joint return. For those living in the United States, the corresponding figures are $50,000 and $75,000, or $100,000 and $150,000 filing jointly.

Estimated payments do not move

The 2026 Form 1040-ES package sets four payment dates: April 15, 2026, June 15, 2026, September 15, 2026, and January 15, 2027. None of the abroad extensions touches them. A self-employed American in Porto holding the December 15 filing extension still owes each 2026 instalment on the ordinary schedule — and the second instalment falls due the same day as the extended 2025 return, so June 15 does double duty.

State clocks — California as the test case

States keep their own calendars, and California’s shows how differently a state can treat the same move abroad. The Franchise Tax Board sets April 15, 2026 as the date to file and pay, with an automatic filing extension to October 15, 2026 — payment still due in April. For a filer living or traveling outside the United States on April 15, both filing and payment move to June 15, 2026, and the automatic extension for those abroad runs to December 15, 2026, with payment due by the June date to avoid penalties. Other states draw these lines elsewhere, and several draw none — a former resident’s obligations depend on the state left behind, not on the federal column.

Portugal — one window, one payment date

Portugal compresses its season into a single window: the Modelo 3 return for 2025 income is delivered between April 1 and June 30, 2026. The Portal das Finanças applies the same window to residents and to non-residents with Portuguese-source income not settled by withholding. Payment follows the assessment — under article 97 of the CIRS, tax assessed within the standard window is paid by August 31. A US citizen resident in Portugal therefore files the American return by June 15, the Portuguese one by June 30, and settles any Portuguese balance by the end of August.

Spain — a campaign, a cutoff, and a March deadline

Spain runs its season as a campaign. For 2025 income, online filing of the Renta and Patrimonio declarations opens April 8, 2026 and closes June 30, 2026. One date inside the campaign matters more than the closing day: a return paid by direct debit — domiciliación — must be filed by June 25, five days before the end. And well before the campaign begins, the informational declaration of assets and rights held abroad, Modelo 720, has its own window: January 1 to March 31, 2026 for positions held during 2025. It is the first deadline of the Spanish year and the one most often discovered late, because it belongs to no tax bill at all.

The dates no extension reaches

Four items sit outside every extension chain:

• Interest on unpaid 2025 US tax — running from April 15, 2026 under every extension, automatic or requested
• The four estimated payment dates — April 15, June 15 and September 15, 2026, and January 15, 2027
• Modelo 720 — its window closes March 31, 2026, before the Spanish campaign has even opened
• The Spanish direct-debit cutoff — June 25, 2026, ahead of the June 30 campaign close

Taken from the payment dates outward, the 2026 season abroad has a simple shape: money moves in April, June and August; paper can follow as late as December.

Sources

1. IRS — U.S. Citizens and Resident Aliens Abroad — https://www.irs.gov/individuals/international-taxpayers/us-citizens-and-resident-aliens-abroad — checked 2026-08-29
2. IRS — Publication 54 (12/2025), Tax Guide for U.S. Citizens and Resident Aliens Abroad — https://www.irs.gov/publications/p54 — checked 2026-08-29
3. IRS — Form 1040-ES (2026), Estimated Tax for Individuals — https://www.irs.gov/pub/irs-pdf/f1040es.pdf — checked 2026-08-29
4. IRS — Report of Foreign Bank and Financial Accounts (FBAR) — https://www.irs.gov/businesses/small-businesses-self-employed/report-of-foreign-bank-and-financial-accounts-fbar — checked 2026-08-29
5. FinCEN — New Due Date for FBARs — https://www.fincen.gov/news/news-releases/new-due-date-fbars-0 — checked 2026-08-29
6. IRS — Do I Need to File Form 8938, Statement of Specified Foreign Financial Assets — https://www.irs.gov/businesses/corporations/do-i-need-to-file-form-8938-statement-of-specified-foreign-financial-assets — checked 2026-08-29
7. California Franchise Tax Board — Due Dates: Personal — https://www.ftb.ca.gov/file/when-to-file/due-dates-personal.html — checked 2026-08-29
8. Autoridade Tributária e Aduaneira — Modelo 3, Apoio ao Contribuinte — https://info.portaldasfinancas.gov.pt/pt/apoio_ao_contribuinte/Cidadaos/Rendimentos/Declaracao/Modelo_3/Paginas/default.aspx — checked 2026-08-29
9. Autoridade Tributária e Aduaneira — CIRS, artigo 97.º, Pagamento do imposto — https://info.portaldasfinancas.gov.pt/pt/informacao_fiscal/codigos_tributarios/cirs_rep/Pages/irs97.aspx — checked 2026-08-29
10. Agencia Tributaria — Fechas de campaña de Renta y Patrimonio — https://sede.agenciatributaria.gob.es/Sede/ayuda/contenidos-lectura-facil/calendario-contribuyente-2026-simplificado-personas-fisicas/fechas-campana-renta-patrimonio.html — checked 2026-08-29
11. Agencia Tributaria — Calendario de la campaña de Renta 2025, junio — https://sede.agenciatributaria.gob.es/Sede/irpf/campana-renta/calendario-campana-renta/junio.html — checked 2026-08-29
12. Agencia Tributaria — Modelo 720, Plazos de presentación — https://sede.agenciatributaria.gob.es/Sede/todas-gestiones/impuestos-tasas/declaraciones-informativas/modelo-720-decla_____sobre-bienes-derechos-extranjero_/plazos-presentacion.html — checked 2026-08-29