Hungarian companies working in Belgium are a smaller group concentrated in specialist industrial and installation work. Hungary does not appear in Belgium’s top ten sending countries, which in practice means fewer advisers who know the route and a higher chance that Belgian formalities are handled for the first time on a live project.
Where Hungary sits in the Belgian market
Hungary falls within the ‘other countries’ group of the Belgian Limosa breakdown, together 36,254 posted persons in 2023, 15.6 percent of the total.
Hungarian activity in Belgium tends towards metalworks, installation and manufacturing-adjacent work rather than general construction, which means assignments are often on industrial sites where the works value comfortably exceeds the Check-in-at-Work threshold even where the Hungarian scope is modest.
The four things you must have
Work backwards from your mobilisation date, because two of these depend on third parties.
1. A1 certificates, applied for at the National Health Insurance Fund, through its Department for International Affairs before departure, one per posted worker, covering the full planned period. They prove your people stay in the Hungarian social security system rather than becoming liable for Belgian contributions. See what Belgian inspectors check on an A1. 2. A Belgian company number (CBE) and portal access, if Check-in-at-Work will apply. Foreign employers need both to register presence at all, and this is the step most often left too late. 3. The Limosa declaration, filed at limosa.be before the first day of work. It produces a LIMOSA-1 receipt each worker must be able to show to the Belgian client. Full detail in our Limosa guide. 4. A liaison person, whose identity and contact details you give to the Belgian Labour Inspectorate, and who can actually be reached about the posting.
Does the A1 replace the Limosa declaration?
No, and this is the most expensive misunderstanding in cross-border work.
The A1 answers which country’s social security system applies. Limosa answers whether Belgium knows your worker is on its territory. They are issued by different bodies for different purposes. An employer holding a valid A1 still has to file a Limosa declaration before the work starts, and an inspector will ask for both.
First-time market entry, on a site that is already registered
The characteristic first-project failure is arriving on a Belgian industrial site where Check-in-at-Work is already running and assuming enrolment is handled for you.
It is not automatic. Responsibility lies both with the party sending the worker and with the person doing the work, and the two must agree who registers and then verify it happened. In addition, a foreign employer needs secure access to the Belgian social security portal and a Belgian company number (CBE) to register at all. Arranging that takes time you will not have on the first morning.
The second common gap is the liaison person. Belgium requires the identity and contact details of someone reachable about the posting to be given to the Labour Inspectorate. Naming a Budapest head-office address with no Belgian-hours contact turns a routine query into an escalation.
When does Check-in-at-Work apply?
Registration is mandatory for works on immovable property, excluding cleaning, and for certain meat-sector activities, where the total value of the works reaches 500,000 euro excluding VAT. The threshold applies whether that value is reached at the start of the works or during them, and it attaches to the works as a whole, not to your own contract value.
Three points that catch foreign contractors:
- It is daily. Registration must happen before the person begins work, every working day, for every person on site. It is not a one-off enrolment.
- Responsibility is shared. It lies both with the party sending the worker and the party doing the work, and the two must agree who registers and verify it happened. Assuming the main contractor covers you is not a defence.
- “Works on immovable property” is broad, reaching well beyond new-build into renovation, fit-out, technical installation and groundworks.
From 1 April 2027, a Programme Law adopted on 30 May 2026 extends the obligation to registering both entry and exit, and brings the supply of ready-mixed concrete into scope. Sign-in sheets will not carry you past that date.
The differences between the systems are set out in Limosa, Dimona or Check-in-at-Work.
What it costs to get wrong
Failing to file a Limosa declaration is a level 4 offence, the heaviest category in the Belgian Social Criminal Code, carrying the possibility of imprisonment alongside financial penalties.
Fines rose on 1 February 2026, when the Act of 19 December 2025 raised the multiplier applied to social criminal fines from 8 to 10. For some infringements the amount is multiplied by the number of workers involved, up to a maximum of 100, which is what turns one administrative gap on a ten-person crew into a serious figure.
There is a commercial cost too. Your Belgian client is exposed through joint and several liability for your workers’ wages, and through the withholding obligation: where a contractor has social or tax debts, the client must withhold 35 percent of each invoice excluding VAT for social security debts and 15 percent for tax debts, checked at checkinhoudingsplicht.be. Since 1 May 2026 a further 15 percent applies for outstanding self-employed contributions. A subcontractor who creates that problem does not get invited back. Our guide for main contractors describes the exposure your client takes on.
Keeping the paperwork and the site in agreement
The hard part of cross-border work is not understanding the rules. It is keeping the file in your home office and the reality on a Belgian site aligned, week after week, as crews rotate and programmes move.
Two habits do most of the work. Treat every crew change as a compliance event: a new person means a new A1 check, a new Limosa entry and site registration under their own identity, arranged before they travel. And capture presence digitally at the moment someone arrives, tied to the person and the project, so the site record matches your declarations by default and you can produce a specific past day on request without reconstructing it.
Suivo’s check-in-at-work is used on Belgian sites where several subcontractors work side by side, and runs on the same workforce management platform as time tracking, so the data you capture for compliance also feeds hours and project costing instead of sitting in a separate system.
See how Cibor manages registration across Belgian sites.
A note on language
Hungarian is not an administrative language in Belgium. Appoint a liaison person able to correspond in English at minimum, and in Dutch or French depending on where your sites are.
If your crews come from several countries, our guide to posting workers to Belgium covers the rules for each.
Book a free demo
If you are bringing Hungarian crews onto Belgian sites and want presence registration that satisfies an inspector without slowing your work down, we will show you how it runs day to day. Book a free demo.
