Swiss Posted Worker Route (Secondment): When the 90-Day Notification Is Not Enough and You Need a Permit

Businesses engaged in cross-border projects frequently assume that Switzerland can be covered by the “90-day notification” route for posted workers. In practice, project scope evolves, deadlines slip and on-site needs increase. The result is that what began as a straightforward secondment can quietly cross the legal threshold into a permit requirement - often discovered only when access badges, site induction or client compliance checks bring the issue to the surface. At that point, timelines become critical and the business impact can be immediate.

This article explains how the Swiss posted worker route works at a high level, why the 90-day notification is not a general “work authorisation”, and how to identify early when a posting will exceed it. It then sets out what to prepare - in particular an assignment plan and supporting documentation - so that, where a permit is required, the application can be made without derailing the project.

Understanding the Swiss posted worker framework: notification is not a permit

Switzerland allows certain short-term work activities by posted workers to be carried out on the basis of an online notification procedure rather than a residence/work permit. The Swiss 90-day notification regime is designed for temporary cross-border service provision and is distinct from a Swiss work permit process. Its practical attraction is speed: the notification can, in principle, be made without waiting for a cantonal permit decision.

However, Switzerland's posted worker notification route is limited. It is not a “blanket” permission to work in Switzerland for any duration, nor does it convert a foreign employment relationship into a Swiss-compliant long-term arrangement. Once the relevant thresholds are exceeded - or where the activity falls outside the scope of what can be notified - a Swiss work authorisation becomes necessary. If this is not identified early, the posting can become unlawful from a Swiss immigration perspective, and the Swiss client or site operator may refuse access for compliance reasons regardless of whether the worker can physically enter the country.

In addition, immigration compliance sits alongside Swiss employment compliance. Posted worker projects often trigger obligations under Swiss rules on minimum salary and working conditions applicable to posted employees, as well as Swiss sector-specific requirements. These are not the focus here, but in real projects they tend to be assessed in parallel by clients and contractors, and immigration planning should be aligned with them.

The 90-day notification in practice: what it covers, and what it does not

The “90 days” commonly referred to is not a single 90-day trip. It is a limited annual quota of workdays in Switzerland that can be used under the notification regime, counted per person. The counting is typically based on actual workdays in Switzerland, not on calendar days spent in the country, which means short rotations can consume the quota quickly without the assignment feeling “long”.

The most frequent reason the notification route becomes insufficient is straightforward: the number of planned workdays in Switzerland for the individual exceeds what can be notified within the relevant reference period. A second reason is structural: the project is no longer a short-term service provision but begins to resemble an ongoing integration of the worker into Swiss operations. That shift can occur even if the total number of days is only marginally above the limit, because immigration authorities and clients examine the reality of the arrangement, not only the headline label of “secondment”.

A third category of issues arises where companies treat the notification route as a cure-all for non-EU/EFTA nationals. In Swiss practice, the individual’s nationality and existing right to work in an EU/EFTA state can be decisive. For many non-EU/EFTA nationals, a Swiss work permit may still be required even for short assignments, and where a permit is required, the application will typically be assessed under Swiss third-country national rules, including labour market considerations.

The practical message is that the Swiss 90-day notification route should be treated as a narrow tool for short, clearly temporary postings. If the assignment plan is uncertain or likely to expand, it is often safer to assume from the outset that a permit may be needed and to build the project timeline accordingly.

Early warning signs that your posting will exceed the 90-day notification route

Problems rarely arise because a project manager deliberately ignores the rules. They arise because the project is planned in “phases”, with each phase fitting under the notification threshold, while the overall programme in Switzerland becomes longer than anticipated. The key is to recognise patterns that almost invariably lead to a work permit requirement.

A strong warning sign is a role that is operationally indispensable on site, such that the worker must attend recurring milestones in Switzerland: repeated commissioning visits, weekly client meetings, recurring shutdown windows, iterative testing and remediation, or long-running supervision. Even if each individual trip is short, the accumulation of workdays tends to exceed the notification allowance.

A second warning sign is reliance on named individuals rather than a fungible team. If a contract or client expectation effectively requires specific people, rotation becomes difficult and the project cannot be kept within the notification limit by swapping personnel. This is common in regulated industries, high-security environments and specialist engineering work.

A third indicator is the increasing “Swiss-ness” of the work arrangement. Where the worker begins to take instructions day-to-day from Swiss-based managers, attends as part of a Swiss team, or is treated by the client as embedded staff, the posting starts to look less like a temporary cross-border service and more like local work performed in Switzerland. That change of character often triggers deeper scrutiny and can make a permit route unavoidable.

Finally, an early red flag is a project plan that has no credible day-counting discipline. If the business cannot answer, at the planning stage, how many Swiss workdays are expected per person over the year, it is not ready to rely on the notification route. Counting should be embedded into the assignment governance, not reconstructed retrospectively.

Building an assignment plan that stands up to scrutiny

If there is any realistic chance that a secondment will exceed the notification route, a structured assignment plan becomes the central risk-control document. It should not be a generic statement that the worker will “provide services”. It should be a living document that links project needs to the immigration strategy.

At minimum, the plan should set out the commercial basis for the posting (for example, the service contract and deliverables), the identity of the sending employer, and a clear explanation of why the work must be performed physically in Switzerland rather than remotely. It should specify the anticipated start date, end date, Swiss work locations, and - critically - a workday forecast per individual. Where rotation is proposed as a compliance measure, the plan should explain how rotation will be implemented operationally, and who is responsible for tracking days and preventing overruns.

The plan should also describe reporting lines and supervision. Swiss authorities and sophisticated end-clients tend to look carefully at whether the worker remains organisationally integrated with the foreign employer (typical for a genuine posting) or is effectively directed as part of Swiss operations (which can point towards a Swiss work authorisation being necessary, or at least towards greater scrutiny). Clarity here helps avoid contradictory narratives later.

Timelines: why “we’ll apply if we need to” is a risky approach

Once the 90-day notification route is no longer sufficient, the project enters a secondment permit world where lead times matter. In Switzerland, work authorisation is administered at cantonal level within a federal framework. Processing times therefore vary by canton and by case type, and they are sensitive to the completeness and internal consistency of the application. For non-EU/EFTA nationals, the assessment is generally more intensive, and time needs to be built in for preliminary checks and supporting evidence.

This is why last-minute discovery is so costly. If a worker is scheduled to be on a Swiss site next week and a permit is required, there may simply be no lawful route to meet that timeline. Even for EU/EFTA nationals, while the legal framework is more facilitative, there are still formalities and, depending on duration and canton, administrative steps that cannot be compressed into a day or two without risk.

The practical approach is to set a “decision point” early in the project: the date by which the business must decide whether it will remain strictly within notification days (with a robust tracking mechanism) or switch to a permit strategy. That decision point should sit well ahead of the first critical on-site milestone, so that any permit application can be prepared and filed without stopping work.

What to prepare when a secondment work permit is likely: documentation and internal alignment

Where a permit is required, delays most often arise not because Swiss authorities are unpredictable, but because the business cannot produce coherent documentation quickly. Preparation should therefore begin as soon as the assignment plan suggests the notification route may be exceeded.

You should expect to assemble, in particular, a clear description of the Swiss work scope and deliverables, evidence of the contractual relationship underlying the posting, and documentation supporting the worker’s role and qualifications. For third-country nationals, the posted worker permit application strategy must be considered carefully: Swiss work authorisation for non-EU/EFTA nationals is limited and generally requires a strong justification, with the case presented in a way that fits Swiss legal criteria and cantonal practice.

Internal alignment is equally important. HR, legal, procurement and the project lead must share the same narrative about why the worker is needed in Switzerland, how long for, and under what supervision. Inconsistent explanations across documents, emails and client communications can create avoidable credibility issues. End-clients increasingly request compliance packs in advance; a coherent permit strategy reduces the risk of commercial disruption.

Although it is tempting to treat the immigration step as an administrative afterthought, it is more accurate to regard it as a gating item: until the correct Swiss work authorisation is in place, the project may not be able to proceed lawfully, and the client may not permit site access.

Avoiding project delays: governance, tracking and contingency planning

Projects that successfully rely on the Swiss posted worker route tend to have three features: disciplined day counting, clear responsibility, and contingency planning. Day counting should be centralised, updated in real time and reconciled against travel records. Responsibility should sit with a named person who can stop further notifications or travel when the limit is being approached, even if doing so is operationally inconvenient.

Contingency planning means identifying, early, what happens if additional on-site work becomes necessary. That can include reserving time in the project plan for a permit application, identifying alternative personnel who can rotate in without breaching the limits, or restructuring deliverables so that more work is completed remotely. The point is not to avoid permits at all costs, but to avoid being forced into an emergency application at the worst possible moment.

In many cases, the most commercially sensible choice is to move to a permit route sooner than the business initially expected, particularly where the Swiss client demands long-term continuity of personnel. Taking that decision early tends to be less disruptive than attempting to “squeeze” the final phase of a project into the last remaining notifiable days.

Conclusion: identify the tipping point early and plan for a permit pathway

The Swiss 90-day notification route is a useful mechanism for genuine short-term postings, but it is narrow and easily exhausted by modern project delivery models. The risk is rarely the initial plan; it is scope creep and cumulative workdays. The most effective protection against last-minute disruption is an assignment plan that counts days per person, explains why Swiss presence is required, and sets an early decision point for moving onto a Swiss posted worker permit strategy where needed.

Where there is any credible possibility that the posting will exceed what can be notified, the legal and operational work should begin early. In Swiss practice, well-prepared applications and coherent project documentation make the difference between a predictable timeline and an avoidable delay.

Contact Our Immigration Lawyers In Switzerland

If you are planning to second staff to Switzerland and are unsure whether the 90-day notification route will be sufficient, we can advise on the appropriate authorisation strategy, supporting documentation and realistic timelines for the relevant canton. To arrange an initial consultation meeting, contact Richmond Chambers Switzerland by telephone on +41 21 588 07 70 or complete an enquiry form.