US Expat Taxes in Europe: UK vs Germany vs Switzerland – Which Country is Hardest to File From?

Moving to Europe can simplify many aspects of daily life, but taxes are rarely one of them for U.S. citizens. Americans living abroad generally remain subject to U.S. federal tax rules on worldwide income, even when they are permanently settled in another country. Depending on where they live, they may also have to file a local tax return.

For U.S. expats in Europe, the problem isn’t just filing two tax returns. It is about understanding how two different tax systems deal with income, investments, pensions, financial accounts, and residency.

The UK, Germany, and Switzerland have their own methods.While complexity varies by individual circumstances, Switzerland generally presents the most complex filing structure overall, followed by Germany, with the UK comparatively easier to coordinate. The following breakdown explains why.

Understanding U.S. Tax Obligations Abroad

In the US, citizens and resident aliens generally are required to report worldwide income regardless of where they reside. Depending on their circumstances, expats may be able to utilise either the Foreign Earned Income Exclusion (FEIE) or the Foreign Tax Credit (FTC) to prevent double taxation.

Foreign financial reporting may add another tier. For example, the Foreign Bank Account Report (FBAR) is typically required if the aggregate value of specified foreign financial accounts exceeds $10,000 at any time during the year. You may also need to file Form 8938 if you have certain foreign financial assets above applicable thresholds.

That means a U.S. expat’s filing requirements can go beyond salary alone. Bank accounts, investments, pensions, rental income and business interests may affect a U.S. return.

US Expat Tax UK: Relatively Familiar, But Not Simple

For many Americans, the UK might be the easiest of the three countries to navigate. The language is familiar, the tax administration is well established and there is an ample amount of guidance available to taxpayers.

However, UK taxes for US expat requirements still require two different systems to be coordinated.

Instead of the U.S. calendar-year system, the UK tax year runs from April 6 through April 5 of the next year. The Statutory Residence Test determines whether you’re a UK tax resident, and considers things like days in the UK, work set-up, accommodation and ties.

Under UK tax rules, a U.S. citizen who is also a UK tax resident may be required to report worldwide income under UK rules.

Where UK Filing Gets Complicated

Income from investments, capital gains, pensions and foreign earnings may have to be carefully coordinated between the two countries. When income or expenses are reported in different currencies, currency conversion can create additional recordkeeping requirements.

There have also been changes in the UK tax system relating to foreign income and gains. The Foreign Income and Gains regime replaced the remittance-basis regime for qualifying new residents from 6 April 2025. This makes current guidance especially applicable to Americans moving to or living in the UK.

UK: Generally more manageable for US expats, though foreign income rules still require careful attention.

US Expat Tax Germany: More Detailed Coordination

Germany can be more challenging for American citizens because the tax system in Germany generally applies worldwide taxation to individuals subject to unlimited tax liability.

A person with a residence or habitual abode in Germany can generally be subject to German income tax on both German and foreign income. For a U.S. citizen, that means two countries may have taxing rights over the same income, requiring careful coordination.

The U.S.-Germany tax treaty and foreign tax credit rules can help address double taxation, but they do not simply eliminate the U.S. filing obligation.

Investments and Pensions Matter

The filing process can become more complicated when a U.S. expat in Germany owns American investments, retirement accounts, rental property, or operates a business.

Currency conversion is another practical consideration. Income earned in euros may need to be reported on the U.S. return in U.S. dollars, while American investment income may need to be considered under German rules.

The interaction between the two systems is often more important than either system viewed independently.

Germany: More demanding due to worldwide taxation and the need to coordinate foreign income and investments. 

US Expat Tax Switzerland: The Most Complex of the Three?

Switzerland often stands out because of its decentralized tax structure. Taxation operates at federal, cantonal, and communal levels, meaning the tax consequences can vary depending on where an individual lives.

For Americans, this creates another layer of coordination on top of U.S. worldwide taxation.

One significant difference is Switzerland’s wealth tax. At the cantonal and communal levels, individuals may be subject to an annual wealth tax based on their net assets  including investments, property, and financial holdings  which is a concept not found in the US tax system and often surprises American expats.  

Why Location Matters in Switzerland

The canton and commune where an expat lives can influence their tax situation. This makes the taxpayer’s canton and commune particularly important when assessing the overall Swiss tax position.

An American living in Switzerland may therefore need to coordinate U.S. income tax, foreign financial reporting, Swiss income taxation, wealth taxation, and the treatment of investments or retirement arrangements.

This does not mean every Swiss return is difficult. A salaried employee with relatively simple finances may have a manageable filing process. Complexity tends to increase as financial assets, investments, pensions, property, or business interests become involved.

Switzerland: Potentially the most complex due to federal, cantonal, and communal taxation layers alongside wealth tax. 

What Actually Makes Expat Filing Difficult?

The country of residence is only one part of the equation. A U.S. citizen with straightforward employment income may have a relatively simple filing experience in any of these countries.

Complexity usually increases when an expat has:

• Multiple sources of income
• Foreign investment or brokerage accounts
• Retirement plans or pensions
• Rental property
• Self-employment or business interests
• Stock compensation
• Significant foreign bank balances
• Financial assets in multiple countries
• Different tax years and reporting deadlines
• A move between countries during the year

Tax treaties can help determine how certain types of income are treated and how double taxation may be relieved. However, treaties do not generally remove the underlying U.S. filing obligation for American citizens.

Which Country Is Hardest to File From?

For many U.S. expats, the UK is likely to be the most straightforward of the three, although the different tax year and rules for foreign income and gains still require attention.

Germany generally presents a higher level of complexity because of worldwide taxation and the need to coordinate foreign income, investments, and U.S. reporting requirements.

Switzerland can be the most demanding because Americans may have to navigate federal, cantonal, and communal taxation alongside wealth tax and U.S. reporting obligations.

Ultimately, there is no single answer that applies to every expat. The hardest filing situation is usually determined by the combination of U.S. citizenship, local tax residence, income sources, investments, financial assets, and personal circumstances.

For anyone comparing US expat tax Germany, US expat tax Switzerland, or UK taxes for US expats, understanding both sides of the tax equation is essential. Treating the U.S. and local returns as separate tasks can overlook important interactions between the two systems.

The most effective approach is to work with an international tax CPA experienced in both US and European tax systems — one who can review applicable requirements together, maintain accurate records throughout the year, and stay current with evolving tax rules across jurisdictions.