Living in Poland with a Ukrainian FOP: where do you pay tax?

If you are a Polish tax resident, you pay tax in Poland on everything you earn, including the income of your Ukrainian FOP (фізична особа-підприємець, a Ukrainian sole trader). You are resident if you spend more than 183 days in Poland in a year, or if your centre of interests (your personal or economic life) is here.

While the FOP stays registered, Ukraine may treat you as its resident too. The 1993 Poland–Ukraine tax treaty then decides where you pay, and it does not clearly cover Ukraine’s single tax.

When do you become a Polish tax resident?

Polish law has two tests, and either one is enough (article 3(1a) of the Personal Income Tax Act, the PIT Act):

A resident pays Polish tax on worldwide income. A non-resident pays only on income earned in Poland, which includes a business carried on in Poland.

The special rule for Ukrainians, until the end of 2026

Some Ukrainians have an easier way to settle the second test. It applies to people covered by the 2022 special act (specustawa, the law on help for Ukrainian citizens, as it stood before 5 March 2026):

• For 1 January 2024 to 31 December 2026, your centre of interests is in Poland if you make a written statement saying so (PIT Act article 52zr).
• The 183-day test is not affected.
• Nothing similar has been enacted for 2027. From 1 January 2027 the ordinary tests apply to everyone.

Watch out: the written statement only settles the Polish side. It does not stop Ukraine from also treating you as resident.

Our general guide to Polish tax residency for foreigners covers moving mid-year and certificates in more detail.

Why a FOP can make you resident in both countries

Ukraine has its own residence test. Its Tax Code (article 14.1.213) says that having your family live permanently in Ukraine, or being registered there as an entrepreneur, is a “sufficient (but not exclusive)” condition for your centre of vital interests being in Ukraine.

So a Ukrainian who lives in Poland and keeps an active FOP can be a tax resident of both countries, each under its own law. The treaty (article 4(2)) breaks the tie in this order:

1. Where you have a permanent home.
2. If you have a permanent home in both: where your centre of vital interests is.
3. If that cannot be settled, or you have a permanent home in neither: where you habitually live.
4. Your citizenship. For a Ukrainian who habitually lives in both countries, or in neither, this points to Ukraine.
5. An agreement between the two tax authorities.

For many people step 1 or 2 already gives the answer. The hard cases are the borderline ones: a flat in each country, family split between them, or long stays in both.

Tip: to prove Polish residence to a Ukrainian client or tax office, ask your Polish tax office for a certificate of residence (certyfikat rezydencji, form CFR-1). It is free through e-Urząd Skarbowy (the tax office’s online service) or the e-US app. On paper, or through e-Doręczenia (the state e-delivery service), it costs 17 PLN. It is issued within 7 days.

Does Ukraine’s single tax count in Poland?

Under the treaty, business income of a Polish resident is taxed only in Poland, unless it comes from a permanent establishment or fixed base in Ukraine (articles 7 and 14). If you do the work at your desk in Poland, the treaty points to Poland.

When the treaty does let Ukraine tax some of your income, Poland mostly uses exemption with progression (wyłączenie z progresją). Poland does not tax that income again, but counts it when setting the rate on the rest.

The OECD multilateral convention (MLI) applies to this treaty. According to the Ministry of Finance’s synthesised text, it did not change this method.

The open question is the single tax (єдиний податок) that many FOPs pay. The treaty names Ukraine’s profit tax and personal income tax, plus any “identical or similar” tax introduced later (article 2). No official source we found says whether the single tax is one of them.

So you cannot assume that paying it in Ukraine lowers or cancels your Polish tax on the same income. If you pay the single tax on work physically done in Poland, and Polish tax as a resident, you may simply pay twice. Get an answer in writing from advisers in both countries, or ask KIS (Krajowa Informacja Skarbowa, the Polish tax information line) on 801 055 055.

For Diia.City workers: if you move to Poland and become resident, Poland taxes your worldwide income too. How the Ukrainian tax is treated depends on your contract type and where you work, and we have not verified the current rules.

Should you close the FOP, keep it, or open a JDG?

A JDG (jednoosobowa działalność gospodarcza) is the Polish sole trader. There is no single right answer. It depends on where your clients are, where your family lives and whether you plan to go back. These are the trade-offs:

A JDG is taxed exactly as for a Pole. You choose the tax scale, the 19% flat tax or ryczałt (a tax on revenue), and file the same returns. See how to choose your tax form.

Not every residence title lets you open one, though. Since 5 March 2026 a new JDG needs PESEL UKR (the PESEL number with temporary-protection status), a CUKR card (the residence card for Ukrainians who had temporary protection) or another listed permit. A temporary residence and work permit is not enough. Running a business in Poland as a Ukrainian explains who qualifies and what happens to JDGs opened earlier.

What Polish clients expect from you

With a JDG you work like any Polish business:

• A NIP (tax number). You get it through your CEIDG application (CEIDG is the public register of sole traders). Registration is free.
• Invoices in KSeF. From 1 April 2026 businesses, including VAT-exempt ones, issue invoices to other businesses in KSeF, the national e-invoicing system. Until 31 December 2026 you may still issue PDF or paper invoices while the invoices you must issue in KSeF total no more than 10,000 PLN gross in a month. From the invoice that takes a month over that, you use KSeF for good.
• Bank payments. When a deal with another business is worth more than 15,000 PLN, you must pay or be paid through your payment account, not in cash. This applies even if the deal is split into instalments.
• Foreign clients. Services to a business abroad are usually taxed where the client is. With an EU business client you must register for VAT-UE (EU VAT registration) before you provide the first service, even if you are VAT-exempt. See invoicing a client abroad.

ZUS: where are you insured?

ZUS is Poland’s social insurance institution. Poland and Ukraine have a social security agreement, in force since 1 January 2014:

• As a rule you are insured in the country where you work (article 6).
• A self-employed person who normally works in one country and moves the activity to the other for a while stays in the first country’s system for up to 24 months (article 7(2)).

The agreement has no specific rule for someone self-employed in both countries at the same time. How ZUS and the Pension Fund of Ukraine treat a person with a FOP and a JDG is unclear. Ask ZUS (22 560 16 00) before you plan around it.

Inside a JDG, ZUS is the same as for Poles. The 2026 figures:

Both reliefs are barred if you ran a business in the 60 months before. Whether a FOP you ran in Ukraine counts, which could block them, is not settled. Ask ZUS for a written interpretation (interpretacja indywidualna ZUS). The details are in ulga na start and preferential ZUS.

What to do next

1. Count your days in Poland in 2026 and write down where your home, family and clients are.
2. If you are covered by the special act, remember that the written-statement rule ends on 31 December 2026.
3. Decide about the FOP with advisers in both countries, before 1 January 2027 if you can, so your 2027 residence is clear.
4. Ask for a CFR-1 if a Ukrainian client or tax office needs proof of Polish residence.
5. Check your residence title before opening a JDG. If you had a FOP, ask ZUS in writing about ulga na start.
6. Keep each business’s invoices and statements apart. Komplet, our free Mac app, files each invoice into the right month in your own folders, so your Polish records stay separate and in one place.