Seat vs. fixed establishment — where the line starts
"Foreign-owned" isn't the same as "foreign". The distinction decides everything that follows.
If you run a Polish company (for example a sp. z o.o., the Polish limited liability company) or a Polish JDG (sole proprietorship), your business seat is in Poland. You're a Polish taxpayer, and the KSeF obligation applies on the standard timeline — regardless of who owns the shares. The FE analysis changes nothing here.
The FE question only matters when your seat is abroad (a parent company in Germany, the Netherlands, Ukraine, and so on) and you merely operate in Poland — a warehouse, staff, a subcontractor, or a VAT registration. MF's guidance is addressed precisely to "taxpayers without a seat of business activity in Poland."
When the KSeF obligation arises — Article 106ga(2)
The obligation to issue structured invoices sits in Article 106ga of the Polish VAT Act. Paragraph 2 lists who is exempt. Under Art. 106ga(2)(1)–(2), a taxpayer need not issue via KSeF if it:
has neither a seat nor an FE in Poland, or
has no Polish seat and an FE in Poland that does not participate in the specific supply for which the invoice is issued.
So having an FE is not enough on its own. The FE must actively take part in the particular transaction. If either element is missing, KSeF is, in principle, optional rather than mandatory.
What an FE is — and when it "participates"
"Fixed establishment" is an EU concept, defined in Article 11 of Council Implementing Regulation (EU) No 282/2011. MF doesn't invent a new definition; it maps the existing EU meaning onto KSeF.
An FE exists only when three conditions are met together:
sufficient permanence (a lasting presence, not a one-off),
an adequate human structure (people),
an adequate technical structure (infrastructure),
organised so the establishment can actually carry out the transaction.
The guidance is explicit about what does not create an FE:
a Polish VAT registration alone (even a simplified one),
merely owning or renting property — an office, warehouse, or plant — because property is just one element,
an FE is also not the same as a "permanent establishment" for corporate income tax (CIT). You can have a CIT PE without a VAT FE, and vice versa.
Active vs. passive FE
The guidance distinguishes an active FE from a passive one — and that distinction drives the obligation:
An active FE genuinely takes part in taxable sales; it is involved in carrying out the transaction. This is what triggers the KSeF obligation.
A passive FE is limited to auxiliary functions — technical support, marketing, PR, handling complaints. If it plays no part in selling or invoicing, no KSeF obligation arises.
Example. A foreign-seated company rents a furnished office in Poland and has staff who follow its instructions and negotiate sales terms. That's an active FE — KSeF applies. But if the same premises and staff are run by an external provider that instructs the workers itself, and the local structure only performs support tasks, an active FE may not arise at all. This tracks CJEU case law such as Titanium (C-931/19) and Berlin Chemie (C-333/20).
What this means for your Polish trading partners
The same test decides how invoices flow — in both directions.
If your foreign supplier has an active FE in Poland, it issues via KSeF and you receive invoices through the system.
If the supplier has no FE (or only a passive one), it isn't required to use KSeF — you'll receive invoices the traditional way (email, PDF, paper). Even if such a supplier voluntarily issues in KSeF, it must still deliver the invoice by the agreed channel, because KSeF then serves only as the issuing system, not the delivery channel.
It works the other way too: if you (a Polish taxpayer) sell to a foreign buyer with no FE in Poland, you still issue the invoice in KSeF, but you must make it available to the buyer outside the system, by an agreed method.
Settle the FE status on both sides of a transaction — otherwise an invoice can simply vanish: issued in KSeF by the seller, never collected by the buyer.
Checklist — how to determine your status
Check your seat. A Polish company or JDG? You're a Polish taxpayer — standard KSeF rules, no further analysis needed.
Seat abroad? Identify whether you have human and technical resources in Poland — your own or made available to you.
Assess permanence and control. Does that structure operate on a lasting basis under your operational control, or is it run by an independent third party?
Check involvement in sales. Does the structure take part in the transactions you invoice (active), or only in support functions (passive)?
Mind the traps. A Polish VAT number and real estate, on their own, don't settle the FE question.
Agree the invoice delivery channel with your Polish partners — on both sides.
If in doubt, consider applying for an individual tax ruling; following MF's guidance gives protection under the Polish Tax Ordinance.
Bottom line
The line between an active and a passive FE is genuinely blurry, and every model — a warehouse, outsourced operations, a mixed structure — needs its own assessment. One thing is certain: if the KSeF obligation does reach you, you'll want tooling that issues and receives structured invoices without friction.
That's exactly what Biurko does — issuing and receiving KSeF invoices, in Polish, English, and Ukrainian. Create an account and try it free for 14 days at biurko.io.
FAQ
Do foreign companies have to use KSeF in Poland? Only if they have a fixed establishment (FE) in Poland that actively takes part in their sales. A Polish VAT registration alone, or simply owning property, doesn't create the obligation. What matters is the actual structure and whether it participates in the invoiced transaction.
Does a Polish VAT registration trigger the KSeF obligation? No. Holding a Polish NIP or EU VAT number doesn't by itself establish an FE. A taxpayer with no seat and no active FE in Poland isn't required to issue invoices in KSeF — it may do so voluntarily.
Is a VAT fixed establishment the same as a CIT permanent establishment? No. An FE is a VAT concept (Article 11 of Regulation 282/2011), while a "permanent establishment" belongs to corporate income tax. MF's guidance stresses they aren't identical — you can have one without the other.
How do I receive an invoice from a foreign supplier with no FE? That supplier isn't required to use KSeF, so you'll receive the invoice traditionally — by email, PDF, or paper. Agree the delivery channel in advance so the invoice doesn't get stuck between systems.
When does KSeF start for foreign companies with an FE? On the same timeline as Polish businesses: 1 February 2026 for the largest taxpayers (2024 sales above PLN 200 million), and 1 April 2026 for everyone else.