7 Tax Mistakes American Expats Make (and How to Avoid Them in 2026)

The United States taxes its citizens on worldwide income no matter where they live, and in 2026, the IRS is enforcing this more aggressively than ever. The Foreign Earned Income Exclusion (FEIE) lets you exclude up to $132,900 from US federal income tax, but that's just one piece of a complicated puzzle. Failing to file an FBAR can trigger penalties up to $165,353 per account per year, and the IRS is now using artificial intelligence to flag non-compliant expat returns. Here are the seven most common tax mistakes American expats make and exactly how to avoid each one.

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Mistake #1: Not Filing a US Tax Return at All

This is the most dangerous mistake, and it's disturbingly common. Many Americans who move abroad assume that because they're paying taxes in their new country, they don't owe anything to the US. Wrong.

The reality: The US requires every citizen and green card holder to file a federal income tax return if their worldwide income exceeds the filing threshold ($14,600 for single filers in 2026). It doesn't matter if you haven't set foot in America in a decade. It doesn't matter if you've paid 40% tax in Germany. You still have to file.

The consequences:

• Failure-to-file penalty: 5% of unpaid taxes per month, up to 25%
• Failure-to-pay penalty: 0.5% per month on unpaid balance
• Loss of eligibility for the FEIE (you must file to claim it)
• Potential passport revocation for seriously delinquent tax debt ($62,000+)

How to avoid it: File every year, even if you owe nothing. If you're behind, look into the Streamlined Filing Compliance Procedures — the IRS's amnesty program for non-willful non-filers. It's far less painful than getting caught.

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Mistake #2: Forgetting FBAR for Joint Accounts and Cryptocurrency

The Report of Foreign Bank and Financial Accounts (FBAR), filed as FinCEN Form 114, is required if the aggregate value of your foreign financial accounts exceeds $10,000 at any point during the year. This catches more expats than any other filing requirement.

What Counts as a "Foreign Financial Account"?

The trap most people miss: If your name is on your spouse's foreign bank account, that account must be reported on YOUR FBAR — even if you've never deposited or withdrawn a single dollar from it. Joint accounts count for both parties.

Cryptocurrency: This is the IRS's current enforcement priority. If you hold crypto on a foreign exchange like Binance, Kraken (for non-US accounts), or any non-US-based platform and the total value exceeds $10,000, you must report it on your FBAR. The IRS has been issuing guidance since 2023 making this explicitly clear.

Penalties for non-willful violations: Up to $165,353 per violation in 2026 (this amount adjusts for inflation annually). Willful violations can reach $100,000 or 50% of the account balance, whichever is greater, plus potential criminal prosecution.

How to avoid it: File your FBAR electronically through the BSA E-Filing system by April 15 (automatic extension to October 15). Report every account where you have financial interest or signature authority. When in doubt, report it.

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Mistake #3: Ignoring Self-Employment Tax When Using the FEIE

Here's a painful surprise that catches many freelance expats: the Foreign Earned Income Exclusion does not cover self-employment tax.

The FEIE can exclude up to $132,900 of your foreign earned income from federal income tax. But if you're self-employed (freelancer, contractor, business owner), you still owe self-employment tax (Social Security and Medicare) at 15.3% on net self-employment income up to $168,600.

Example

That $14,130 bill shocks a lot of people who thought the FEIE made them tax-free.

How to avoid the sting:

• If your country has a Totalization Agreement with the US (30+ countries including UK, Germany, France, Canada, Australia, South Korea), you may be exempt from US self-employment tax while paying into the foreign social security system
• Consider structuring your business as an S-Corp to reduce self-employment tax exposure (consult a tax professional)
• Set aside 15% of net self-employment income for this obligation throughout the year

For more on managing finances as an expat, visit our finance resources.

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Mistake #4: Failing the Physical Presence Test

To claim the FEIE, you must meet either the Bona Fide Residence Test or the Physical Presence Test. Most nomads and newer expats use the Physical Presence Test, and many miscalculate it.

The rule: You must be physically present in a foreign country (or countries) for 330 full days during a 12-month period. That 12-month period does not have to be a calendar year — it can be any consecutive 12-month block.

Where people mess up:

• Transit days count as US days. If you fly from London to Bangkok with a 4-hour layover at JFK, that's a US day. You just lost one of your 35 allowed US days.
• Partial days count. If you land in the US at 11:55 PM, that entire day counts as a US day.
• 35 days is the maximum, not a target. You can spend up to 35 days in the US (365 minus 330), but many expats cut it close and then have a family emergency that pushes them over.
• "Foreign country" means not the US. International waters and airspace don't count as foreign country presence.

How to avoid problems:

• Keep a detailed travel log with dates, flights, and countries
• Build in a buffer — aim for 340+ days abroad rather than exactly 330
• Save boarding passes, passport stamps, and apartment leases as documentation
• Use a 12-month period calculator (many expat tax software tools include one)

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Mistake #5: Forgetting FATCA Form 8938

FATCA (Foreign Account Tax Compliance Act) requires filing Form 8938 with your tax return if your foreign financial assets exceed certain thresholds. This is separate from the FBAR — you may need to file both.

Filing Thresholds for Expats

Key differences from FBAR:

• Form 8938 goes to the IRS with your tax return; FBAR goes to FinCEN separately
• Form 8938 has higher thresholds (especially for expats living abroad)
• Form 8938 includes a broader range of assets (foreign stocks, partnership interests, financial instruments — not just bank accounts)

Penalty for non-filing: $10,000 for failure to file, with additional penalties up to $50,000 for continued non-compliance after IRS notification.

How to avoid it: If you have significant foreign assets, calculate your totals against both FBAR and FATCA thresholds. File both when required. They serve different purposes and go to different agencies.

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Mistake #6: Forgetting State Tax Obligations

Moving abroad doesn't automatically end your state tax obligations. Several US states continue to consider you a resident (and tax you accordingly) unless you take specific steps to establish domicile elsewhere.

States That Are Hard to Leave (Tax-Wise)

• California: Presumes you're still a resident unless you can prove permanent departure. Known for aggressive audits of former residents.
• New York: Similar to California. Maintaining any "ties" (apartment, storage unit, driver's license) can trigger residency.
• Virginia: Requires filing a "Declaration of Domicile" in your new location.
• New Mexico: Continues to tax residents even if living abroad.
• South Carolina: Maintains residency if you "intend to return."

States with no income tax (easier to establish as last domicile): Florida, Texas, Nevada, Wyoming, Washington, Tennessee, South Dakota, Alaska, New Hampshire (no earned income tax)

How to avoid it:

• Before moving abroad, establish domicile in a no-income-tax state if possible
• Get a driver's license, register to vote, and open a bank account there
• Surrender your old state's driver's license
• File a final/part-year return with your former state
• Keep documentation proving you've severed ties

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Mistake #7: Using Wrong Exchange Rates

The IRS requires that all foreign currency amounts be converted to US dollars on your tax return. Using the wrong exchange rate — or being inconsistent — is a red flag.

IRS accepted methods:

1. Annual average exchange rate (published by the IRS for major currencies) — use this for income received throughout the year
2. Spot rate on the date of transaction — use this for specific large transactions
3. Treasury Department's exchange rate — the official fallback

Common mistakes:

• Using Google's exchange rate on April 15 instead of the IRS's published annual average
• Using different rate sources for different items on the same return
• Not converting foreign tax payments to USD when claiming the Foreign Tax Credit
• Using the wrong year's exchange rate

How to avoid it: Use the IRS's own published average annual exchange rates, available at irs.gov. Be consistent across your entire return. Document which rates you used and where you sourced them.

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The IRS Is Using AI to Catch Non-Compliance

Starting in 2025, the IRS significantly expanded its use of artificial intelligence and machine learning to identify non-compliant expat returns. The Inflation Reduction Act funding has given the agency resources it hasn't had in decades.

What this means for expats:

• Cross-referencing international data: FATCA reporting from foreign banks is being matched against filed returns. If your foreign bank reported your account to the IRS but you didn't file Form 8938, the AI flags it instantly.
• Pattern recognition: The IRS is identifying expats who claim the FEIE but show spending patterns inconsistent with foreign residence (credit card use concentrated in the US, for example).
• Crypto tracking: Blockchain analytics firms are contracted to trace cryptocurrency movements, even across decentralized platforms.
• Whistleblower tips: The IRS pays informants 15–30% of collected taxes for tips leading to enforcement actions over $2 million.

The era of "the IRS doesn't have the resources to come after expats" is ending. Compliance is no longer optional — it's urgent.

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What to Do If You're Behind

If you've been living abroad and haven't been filing, don't panic — but do act quickly.

Streamlined Filing Compliance Procedures:

• Available for non-willful non-filers
• File 3 years of back tax returns + 6 years of FBARs
• Pay any tax due plus interest (but no penalties for most expats living abroad)
• Self-certify that your failure to file was non-willful

Voluntary Disclosure Practice:

• For willful non-filers or those with large undisclosed accounts
• More complex, typically requires professional representation
• Avoids criminal prosecution in exchange for full disclosure and penalty payment

The cost of professional help: An expat tax specialist typically charges $500–$2,000 for annual filing, or $2,000–$5,000 for Streamlined Procedure filings. It's worth it. The penalty for a single willful FBAR violation can exceed the cost of a decade of professional tax preparation.

Explore more expat financial guidance on our finance resources page, and if you're still deciding where to move, our country rankings can help you find destinations with favorable tax treaties.

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Frequently Asked Questions

Do I still need to file if I earn under $132,900? Yes. You must file a return to claim the FEIE. Without filing, the exclusion doesn't apply, and you technically owe tax on your full worldwide income.

Can I use both the FEIE and Foreign Tax Credit? Not on the same income. You can use the FTC on income above the FEIE exclusion, but you cannot double-dip on the same dollars. For high earners, the FTC alone is sometimes more beneficial.

What happens if I renounce my US citizenship? You'll face an exit tax on unrealized gains if your net worth exceeds $2 million or average tax liability exceeds ~$206,000 over the past 5 years. You must also be current on all filings for 5 years before renunciation. It's complex — get professional advice.

Are there any countries where I won't owe US tax? No. The US taxes worldwide income regardless of where you live. However, countries with tax treaties and Totalization Agreements can reduce or eliminate double taxation.