9 Costly Tax Mistakes Expats Make When Moving to Europe

Moving to a new European country is exciting. Dealing with a new tax system is not. These are the mistakes we see most often — and each one can cost you thousands of euros.

1. Not applying for special tax regimes in time

Spain's Beckham Law requires application within 6 months of starting work. The Netherlands' 30% ruling must be requested within 4 months of starting employment. Portugal's IFICI has its own deadline. Miss these windows and you lose years of tax savings — potentially €50,000+.

Fix: Research special regimes BEFORE you move. Apply on day one of employment, not when you "get around to it."

2. Staying registered in your home country

Many expats don't formally deregister from their home country's tax system. This creates dual tax residency — you could be liable for tax in both countries simultaneously. Most countries consider you a tax resident if you have a permanent home there, so just moving abroad isn't enough.

Fix: Officially deregister from your home country. In Germany, this means Abmeldung at the Bürgeramt. In the UK, inform HMRC with form P85.

3. Not filing a tax return in Germany

Germany doesn't require most employees to file a tax return — but you almost always should. The average refund is over €1,000. If you paid for job-related expenses, moved for work, or worked part-year, you're likely owed money back.

Fix: File a Steuererklarung every year. Use Taxfix, SteuerGo, or Wundertax for English-friendly filing.

4. Paying church tax by accident in Germany

When you register at the Bürgeramt (Anmeldung), they ask your religion. If you say "Catholic" or "Protestant," you'll be automatically enrolled in Kirchensteuer — an 8-9% surcharge on your income tax. On a €60,000 salary, that's roughly €1,200/year.

Fix: If you don't want to pay church tax, state "keine Konfession" (no religion) or "konfessionslos" at registration. Leaving the church later requires a formal declaration at the Amtsgericht or Standesamt — and costs €30-50.

5. Ignoring double taxation agreements

If you have income from your home country (rental property, investments, pension), you might be taxed on it in both countries. Most European countries have Double Taxation Agreements (DTAs) that prevent this — but you need to actively claim relief.

Fix: Check the DTA between your countries. You may need to file forms in both countries to claim tax credits or exemptions.

6. Not claiming the 30% ruling in the Netherlands

Many skilled expats in the Netherlands qualify for the 30% ruling but never apply because they don't know it exists, or their HR department doesn't mention it. This can cost €5,000-10,000/year in unnecessary tax.

Fix: Ask your employer about the 30% ruling before you start. It must be included in your employment contract.

7. Choosing the wrong German tax class

Married couples in Germany who stay in Class 4/4 when they should switch to Class 3/5 lose up to €400/month. This is essentially an interest-free loan to the government that you get back only when you file your tax return (if you file at all).

Fix: If you're married and one spouse earns significantly more, visit the Finanzamt and switch to Class 3/5 immediately.

8. Forgetting about social security totalization

Years of social security contributions in one country can count toward pension eligibility in another — but only if the countries have a totalization agreement. If you work 3 years in Germany and then 2 years in France, those years can be combined for pension purposes under EU rules.

Fix: Keep records of all social security contributions in every country. When you retire, apply for pensions in each country where you contributed.

9. Not understanding Quellensteuer in Switzerland

Expats without a C permit in Switzerland are taxed at source (Quellensteuer). Many assume this is their final tax and never check. But the Quellensteuer rates are approximations — you might be owed a refund, especially if you have deductions (commuting, childcare, third-pillar pension contributions).

Fix: File an ordinary tax return in Switzerland (mandatory above CHF 120,000, optional below). Many expats get CHF 2,000-5,000 back.