Short answer
The European whistleblowing directive applies in all member states, but is not identical legislation across all of them. Each country has transposed the directive into its own national legislation, making its own choices on details such as precise terminology, the supervisory authority, and sometimes scope. For an organization with establishments in multiple EU countries, this means the obligation itself must be assessed per country, even though the underlying principle is the same everywhere.
This is also the reason why there is no simple answer to whether one central reporting channel suffices. Technically, it often can, and many organizations choose that approach. Whether it meets what each country legally requires of you depends on the national law applicable to that establishment. Anyone seeking certainty on this should consult the national legal text or a lawyer in the country in question.
Why the rules differ per country
The directive is what lawyers call minimum harmonization: it sets a floor that all member states must meet, but leaves room to go further or fill in parts differently. Some countries have chosen, for example, a broader circle of persons entitled to report, or additional obligations in specific sectors, regardless of employee numbers. Other countries have set the designated supervisory authority or the precise wording of deadlines somewhat differently from neighboring countries.
The result is that two establishments of the same enterprise in two different countries may formally fall under two different laws that are substantively very similar but worded slightly differently in certain respects. For an SME entrepreneur with, say, an establishment in the Netherlands and one in Belgium or Germany, this is a real point of attention, even if business operations are otherwise set up identically.
One channel, multiple jurisdictions
A central, hosted reporting channel such as signalo.eu can work for multiple countries at the same time: the technology makes no distinction between establishments. What does require attention per country is whether the procedure, the language, and the deadlines used align with what the local law of that establishment expects. An employee in another country must be able to understand the reporting page and can rely on the procedure fitting what is locally mandatory.
For this reason, it is wise to check per country what additional requirements apply before rolling out one procedure organization-wide. This may involve the language in which reporting must be possible, an additional reporting option to a local supervisory authority, or a detail in the deadlines that is set slightly differently than you are used to. in a few questions see whether the obligation applies to your organization provides an initial direction, but does not replace an assessment per establishment.
What this means in practice
For most SME organizations with one main office in the Netherlands and perhaps a small office elsewhere, the impact is limited: the Dutch rules remain the starting point for the Dutch legal entity, and the law of that country applies to the foreign establishment. Only with larger international structures, with multiple legal entities or establishments that independently fall under the reporting obligation, does it become worthwhile to have it systematically investigated per country what exactly is required.
It is good to understand that a platform such as signalo.eu facilitates and structures the procedure, the deadlines, and the documentation, but does not assess whether your specific international structure meets all local requirements. That assessment lies with you, possibly with a lawyer familiar with the national legislation of the country in question. In the knowledge base with rules by subject you will find the source of the European directive itself, as a starting point for further investigation.
Keep track without becoming a lawyer
You don't need to know all national laws yourself in order to act responsibly. It helps to map out in advance which locations in which countries fall under the reporting obligation, and to have a brief check done per country to see whether anything differs from the Dutch situation. This way you avoid discovering later that a detail was regulated differently in another country than you had assumed.
You can read more about how the information on signalo.eu is structured and where it comes from on the page on how we maintain the information. If you encounter a specific situation that is not covered in the knowledge base, then the overview of frequently asked questions often provides a useful starting point.
Do you want to know where your organisation currently stands, with or without foreign locations? Take the free quick scan or browse through the knowledge base; both are accessible without an account and provide an initial, factual direction.