US expats in Czechia: filing taxes in two countries without paying twice

Most countries tax you for where you live. The United States taxes you for what is in your pocket: a passport or a green card. So an American who moves to Prague joins two tax systems at once, and the job for the first few years is making sure they do not both bill you for the same crown.

It is less frightening than it sounds, and it goes wrong mostly through forms, not money. Treat this as a map, then take your own papers to a professional.

Two systems, two questions

The United States taxes citizens and green card holders on income from anywhere in the world, resident abroad or not. If your income is above the filing threshold you file a federal return every year, even when reliefs bring the bill to zero. Americans living abroad get an automatic two-month extension, from 15 April to 15 June, to file the federal return (as of 2026; check the IRS). Any tax owed still accrues interest from April.

Czechia taxes tax residents on worldwide income. You are generally a resident if you have a permanent home here or stay at least 183 days in a calendar year (as of 2026; check the Financial Administration). Non-residents pay only on Czech-source income. Czech return deadlines are 1 April on paper, 1 May online, and 1 July if a tax adviser files for you. Many employees never file at all, because the employer settles the tax through payroll. Our guides to filing a Czech tax return and Czech tax residency cover the Czech side, and gross versus net pay shows what leaves your salary each month.

How double taxation is avoided

Three tools do the work.

1. The treaty. The United States and Czechia signed an income tax treaty in 1993. It decides which country may tax which kind of income. It does not cancel your US filing duty.
2. The foreign tax credit. Tax you pay in Czechia can generally be credited against US tax on the same income.
3. The foreign earned income exclusion (FEIE). If you pass either the bona fide residence test or the physical presence test (330 full days outside the US in a 12-month period), part of your earned income abroad can be left out of US taxable income. You have to claim it on the return. Nobody applies it for you.

Which tool saves you most depends on your pay, your family, how you are paid and whether you are employed or self-employed. Picking one over the others can have knock-on effects, so this is a question for a cross-border adviser.

The forms people forget

Even if you owe nothing, America wants to know about your money abroad.

• FBAR (FinCEN Form 114). If the combined value of your foreign financial accounts passes USD 10,000 at any point in the year, you must file a report with the Treasury's FinCEN, online and separately from your tax return. A Czech current account counts. The report is due on 15 April, with an automatic extension to 15 October (as of 2026; check FinCEN).
• Form 8938. Some people also list foreign assets on the tax return itself. The thresholds depend on filing status and on whether you live abroad.
• The taxpayer number at the bank. Czech banks routinely ask Americans for a US taxpayer identification number, because of US account-reporting rules. It is the reason some newcomers hit friction opening an account. Our guide to opening a bank account as a foreigner covers the practical side.

Social security and savings

The two countries also have a totalisation agreement on social security, in force since 2009. Its job is to stop you paying into both systems for the same work. Self-employed people and assignments sent from the US follow their own rules, so check which applies. Our guide to Czech social security and pensions explains the Czech side.

Retirement accounts are the other awkward corner. Czech law may treat a US pension or IRA differently from US law, so ask before you move or withdraw anything. If you are paid in Czech crowns by a Czech employer and also invest on the side, our piece on crypto taxes in Czechia shows how another asset class lands on the Czech return.

Finding the right accountant

You want someone who knows both systems, not one who "also does US returns". Our guide to finding a tax adviser or accountant in Prague lists the questions to ask. The US Embassy in Prague publishes notes for citizens, and the IRS has a page for taxpayers abroad.

A sensible order

Settle your Czech payroll and tax residence first. Gather your Czech income records. Work out your US filing position for the year. Only then decide with your adviser which reliefs to claim. Done in that order, spring is calm instead of a scramble.

Frequently asked questions

Do I have to file a US return if I live in Czechia?

Generally yes, if you are a US citizen or green card holder with income above the filing threshold. Reliefs may reduce the tax to zero, but the filing duty usually stays.

Am I taxed twice?

Not normally on the same income. The treaty, the foreign tax credit and the FEIE are designed to prevent it, but you must claim them correctly.

What is the FBAR?

A separate report of foreign accounts filed with FinCEN when their combined value passes USD 10,000 at any time in the year. Due 15 April, automatically extended to 15 October.

When is the US federal return due if I live abroad?

15 April, but Americans abroad get an automatic extension to 15 June. Any tax due still carries interest from April.

Czech accountant or US one?

Ideally one who handles both. A specialist in cross-border tax for Americans abroad is the safest choice.

This is a general explainer, not legal or tax advice.