RUT Registration Step by Step: Polish Agency Guide 2026

For any Polish staffing agency sending workers to Danish construction sites, RUT registration is not a formality to handle at leisure, it is a legal obligation that must be completed before the first worker sets foot on site. The RUT system, short for Registret for Udenlandske Tjenesteydere (Register of Foreign Service Providers), is administered by Arbejdstilsynet, Denmark's national labour inspectorate. Getting it right from the start protects the agency, the client company, and the workers themselves.

What Is RUT and Why Does It Matter?

Denmark introduced the RUT register to give authorities visibility over foreign companies and self-employed individuals providing services on Danish soil. When a Polish agency posts workers to a Danish building site, the agency is classified as a foreign service provider operating temporarily in Denmark. The obligation to register arises directly from Danish law governing posted workers, and Arbejdstilsynet has the power to issue fines for non-compliance or late registration. Inspectors routinely check RUT status during site visits, and if your workers are on site without a valid registration, the consequences can be significant. For more on what happens when inspectors arrive unannounced, see our detailed overview in Arbejdstilsynet Inspection on a Danish Site: 2026 Guide.

Step 1: Check Eligibility and Scope

Before opening the registration portal, confirm that your assignment actually triggers a RUT obligation. The registration requirement applies when a foreign company sends at least one employee to perform work in Denmark for a period that exceeds a short, occasional threshold. In practice, virtually all construction postings require registration. Self-employed individuals from Poland working on their own account in Denmark must also register separately. If your agency is both supplying labour and acting as a subcontractor, clarify which legal entity is the service provider, this determines who registers and who bears liability.

EU Posting Rules and Polish Law

The assignment must also comply with the EU Posted Workers Directive, which sets minimum standards for pay, working time and safety that the host country, Denmark, can enforce. On the Polish side, the agency must ensure workers are properly documented under Polish social security rules administered by ZUS and that the employment contract meets the requirements of the Kodeks Pracy (Polish Labour Code). Workers posted abroad retain their Polish social insurance coverage, typically evidenced by an A1 certificate issued by ZUS. This certificate should be in the worker's possession before departure.

Step 2: Gather the Required Documents

Registration itself is digital, but you need accurate information ready before you begin. Prepare the following: the agency's full legal name and registered address in Poland, the Polish tax identification number (NIP), the name and contact details of a responsible person in Denmark, the address of the Danish work site, the planned start and end dates of the assignment, and the names and personal identification details of all workers being posted. Each worker's A1 certificate from ZUS should already be issued at this stage. Without it, the worker's social insurance status in Denmark is unclear, which creates problems both for the agency and for the worker.

Step 3: Complete the Registration Form on the RUT Portal

Arbejdstilsynet operates the RUT portal at virk.dk, Denmark's central business portal. Foreign companies can register without a Danish CVR number by selecting the option for foreign service providers. The form asks for the company's country of establishment, the nature of the services provided, the work site address, and the details of each posted worker. Take care when entering dates: the registration must be submitted no later than the first day of work. Many agencies make the mistake of registering after workers have already started, this is a violation even if the delay is only a day.

Language and Technical Requirements

The portal is available in Danish and English. If your contact person handles the registration in English, the information submitted is still legally valid. Save a copy of the confirmation receipt the system generates. This reference number is proof of registration and should be available on site in case of an inspection.

Step 4: Submit and Notify the Danish Client

Once you submit the registration, inform the Danish construction company or main contractor immediately. Under Danish rules, the client company also has obligations to verify that foreign service providers are registered. Sharing your RUT confirmation number with the site manager creates a clear paper trail and avoids misunderstandings. Consider this part of your standard onboarding checklist for every new assignment.

Step 5: Manage Changes and Extensions

A RUT registration is not static. If the assignment is extended, the end date must be updated in the portal before the original end date passes. If additional workers join the project after the initial registration, they must be added. If the work site address changes, for example, the agency's workers move from one building to another under the same contract, check whether a new registration or an amendment is required. Arbejdstilsynet's guidance on this is available at at.dk.

Common Mistakes Polish Agencies Make

The most frequent error is registering too late, submitting the form on the morning of day one rather than the day before. Another common problem is listing an incorrect work site address, which matters because inspectors use the registered address to plan site visits. Agencies also sometimes fail to update the registration when workers are swapped out mid-project. Finally, some agencies confuse RUT registration with tax registration at Skattestyrelsen via skat.dk, these are two separate obligations and both may apply depending on the length and nature of the assignment.

Proper record-keeping sits alongside registration as an ongoing duty. Denmark requires employers to retain working time records for a period of five years, and posted workers fall within scope of this rule. For a detailed breakdown of what to store and how, read our guide on 5-Year Working Time Records in Denmark: What to Archive in 2026.

Practical Advice Before Day One

Build a registration checklist into your agency's standard operating procedure for every Danish posting. Assign one person, ideally a compliance coordinator, who owns the RUT process end to end. Set an internal deadline of at least two business days before the posting starts, giving time to correct any errors the portal flags. Make sure every worker carries a printed or digital copy of their A1 certificate and knows the RUT reference number for their assignment.

When issues arise on site, whether a worker questions their working conditions or a misunderstanding develops with the Danish client, having clean documentation makes every conversation easier. For guidance on handling those moments professionally, see Difficult Conversations With Workers on a Danish Site 2026.

RUT registration is ultimately a straightforward process when approached systematically. The agencies that run into trouble are almost always those treating it as an afterthought. Treat it as the first task on every new project, and the rest of the compliance picture becomes significantly easier to manage.