For many companies based in Slovenia, expanding activities to the Netherlands often begins with a straightforward plan. A project is secured, employees are available and the most efficient solution is to deploy the existing team across the border. Within the European Union, that step feels logical and accessible.
In the initial phase, the structure appears manageable. Employees remain on Slovenian payroll, an A1 certificate is requested and the assignment is presented as temporary. For EU nationals, this framework generally works as expected.
However, the situation becomes fundamentally different when Third-Country Nationals are involved.
In practice, many Slovenian companies employ skilled workers who do not hold EU nationality. These employees are fully integrated into the organization in Slovenia and are essential to project delivery. When they are deployed to the Netherlands, the assumption is often that the existing structure simply continues to apply. This is where the 90-day rule becomes critical.
The 90-day rule in practice
Under Dutch immigration rules, Third-Country Nationals who are legally employed in another EU member state may, under specific conditions, work in the Netherlands for a limited period of up to ninety days within a 180-day timeframe. At first glance, this appears to offer a flexible and efficient solution for short-term assignments. In practice, however, the application of this rule is far from straightforward.
Dutch authorities do not assess the situation based solely on the existence of a valid residence permit in Slovenia. They look at how the work is organized in reality. They examine whether the activities in the Netherlands fall within the scope of the original employment, whether the posting is genuinely temporary and whether the foreign employer maintains an active role.
This is where things often go wrong.
Assignments are extended beyond the initial timeframe. Workers return multiple times within short intervals. The line between short-term deployment and structural presence becomes blurred. From a business perspective, these decisions are often driven by necessity. Projects evolve, timelines shift and continuity becomes essential.
From a regulatory perspective, however, the 90-day threshold is not flexible. Once it is exceeded, or incorrectly applied, the legal basis for working in the Netherlands may no longer be valid. At that point, a different immigration route is required, typically involving a Dutch residence and work permit.
Authorities actively monitor this. During inspections, they do not only check documentation, but also travel patterns, duration of stay and the actual nature of the work performed. What appears to be a series of short-term assignments can quickly be interpreted as a continuous presence.
How CIS supports and adds value
This is where CIS plays a decisive role. We support Slovenian companies, among others, before and during their activities in the Netherlands by ensuring that the 90-day rule is applied correctly and, just as importantly, that its limits are clearly understood. Our approach starts with assessing whether the intended activities actually fall within the scope of short-term mobility, or whether a different route should be considered from the outset.
When the 90-day framework is applicable, we guide the full notification process and ensure that all required conditions are met. This includes verifying the underlying employment structure and aligning the documentation with Dutch requirements questioned by authorities.
Where many organizations encounter difficulties is in the ongoing management of these assignments. Days are counted incorrectly, overlapping periods are overlooked and repeat deployments are not always assessed in relation to the 180-day timeframe. CIS provides clarity in this process, helping clients maintain oversight and avoid unintended breaches.
When projects extend beyond the short-term threshold, we proactively advise on the appropriate next steps. Instead of reacting after an issue arises, we help organizations transition to the correct immigration framework in time, ensuring continuity without exposing the business to unnecessary risk.
Ultimately, our added value lies in bridging the gap between operational reality and legal requirements. We understand the pressure to deliver projects and the need for flexibility, but we also understand how quickly that flexibility can turn into exposure if the underlying rules are not applied correctly.
From Slovenia to the Netherlands, the 90-day rule offers opportunity. But only when it is used with precision. And that is exactly where CIS makes the difference.