How to handle Limosa, daily site registration, and automated compliance with Suivo
Your company has just won a contract on a Belgian construction site. The planning is in place, the crew is ready but before anyone crosses the border, there’s a critical administrative step that many Dutch contractors underestimate: Checkinatwork (CIAW).
CIAW is Belgium’s mandatory electronic attendance registration system for construction sites, meat processing, and cleaning. For Dutch companies, the process is more complex than for Belgian firms because of an essential extra requirement: the Limosa declaration. Miss either step the pre-registration or the daily check-in and you face fines of €600 to €6,000 per worker, per day.
This guide walks you through every step: what CIAW is, how it connects to Limosa, what triggers an inspection, and how to automate the entire process so your teams can focus on the actual work.
Get started with automated compliance via Suivo’s Check-in at Work solution.
Quick Navigation
- What Is Checkinatwork (CIAW)?
- Which Sectors Require CIAW?
- The Limosa Connection: Why Dutch Companies Have an Extra Step
- Step by Step: From Limosa to Daily Check-In
- Fines and Inspection Consequences
- Automating CIAW with Suivo
- Quick Compliance Checklist
- Frequently Asked Questions
What Is Checkinatwork (CIAW)?
Checkinatwork is the Belgian government’s electronic attendance registration system, managed by the NSSO (RSZ Rijksdienst voor Sociale Zekerheid). Its purpose is to combat undeclared work, social fraud, and unsafe working conditions by creating real-time visibility into who is present at which location.
The rule is straightforward: every person performing work on a qualifying Belgian site must check in via the CIAW system before work begins not upon arrival, but before the first task starts. This applies every single working day.
For Belgian companies, check-in happens using the national social security number. For Dutch and other foreign companies, the process requires an additional step: the Limosa declaration, which we’ll cover in the next section.
Which Sectors Require CIAW?
CIAW is mandatory in three sectors in Belgium:
| Sector | Threshold | Scope |
| Construction | Projects ≥ €500,000 (excl. VAT) with RSZ site declaration | All real estate works: building, renovation, infrastructure, demolition |
| Meat processing | Always mandatory, regardless of value | All activities in meat processing facilities |
| Cleaning | Always mandatory, regardless of value (threshold abolished Jan 2024) | Third-party cleaning of immovable property (CIAO system) |
⚠️ Who must register? Everyone who sets foot on a qualifying site must be checked in before work starts no exceptions. This includes your own employees, freelancers, self-employed subcontractors, staff from subcontractors, and temporary agency workers.
The Limosa Connection: Why Dutch Companies Have an Extra Step
This is where many Dutch contractors make a costly mistake. Belgian companies check in using their national social security number. Dutch and other foreign companies cannot instead, they need a Limosa declaration for every worker before entering Belgium.
The Limosa declaration (L1) is a mandatory pre-registration with the Belgian authorities, notifying them who will be working, where, and for how long. Without a valid Limosa declaration, your employee simply cannot be registered in the CIAW system.
❌ The most common mistake: Many Dutch companies believe that completing the Limosa declaration means they are fully compliant. That is an expensive misconception. Limosa is the one-time pre-registration. CIAW is the daily check-in on site. Missing the daily registration puts you immediately at risk of a fine even if your Limosa paperwork is perfect.
| Aspect | Limosa Declaration | CIAW Registration |
| What it is | One-time pre-registration with Belgian authorities | Daily attendance registration on site |
| When | Before the worker enters Belgium | Every working day, before work starts |
| Frequency | Once per assignment (may need renewal) | Every single day on site |
| Managed by | Belgian Federal Government (Limosa portal) | NSSO (RSZ) via Checkinatwork system |
| Output | L1 document with Limosa number + QR code | Digital registration in RSZ database |
| Without it | Worker not permitted on site | Fine of €600–€6,000 per worker per day |
Step by Step: From Limosa to Daily Check-In
Here’s the complete workflow for a Dutch company sending workers to a Belgian site:
Step 1: Submit the Limosa declaration before departure
Before any worker crosses the border, submit the Limosa declaration via the official Limosa online portal. You’ll declare who is going, which site they’ll work on, and for how long. This must be completed before the employee arrives in Belgium.
Step 2: Receive and store the L1 documents
After the declaration, you receive an L1 document for each employee containing a unique Limosa number and QR code. Store these securely workers will need them for daily CIAW registration, and inspectors may request them on site.
Step 3: Obtain the RSZ site number from your Belgian client
Your Belgian client or main contractor must provide you with the official RSZ site number for the project. This number links your workers’ registrations to the correct construction site in the NSSO database.
Step 4: Check in every working day before work starts
Each worker uses their Limosa number to register in the CIAW system every morning, before the first task begins. This can be done via the RSZ website, a mobile app, or much more reliably through an automated system like Suivo (covered in the next section).
Fines and Inspection Consequences
The Belgian Labour Inspectorate conducts regular and unannounced checks on construction sites. The penalties for non-compliance are substantial:
- €600 to €6,000 fine per violation, per employee, per day
- Repeat violations can lead to higher sanctions and work stoppages on site
- Clients and main contractors can be held jointly liable if their subcontractor is non-compliant
- Under Belgium’s 2026 due diligence rules, prime contractors must verify the compliance status of all subcontractors in high-risk sectors including construction and cleaning
Given that an average construction project has dozens of workers on site, the total cost of a serious inspection can escalate to tens of thousands of euros within a single day. For Dutch companies, there’s an added risk: if your Limosa declarations are expired or missing, the CIAW registration cannot be completed at all meaning every worker on site is in violation.
Automating CIAW Registration with Suivo
Manual check-ins every morning, for every employee, via the RSZ website are slow, error-prone, and impractical for multi-site operations. Most professional contractors solve this with Suivo: a Belgian IoT platform with a direct, official connection to the RSZ database.
Here’s how the automated workflow looks:
1. Link employee data and Limosa numbers in the Suivo Platform
Enter your Dutch employees’ details in Suivo’s central dashboard and link each person’s unique Limosa number (from their L1 document) to their profile. This is the foundation of correct CIAW registration.
2. Define the RSZ site using geofencing
Draw a virtual boundary around the Belgian work location in Suivo’s map interface. Attach the official RSZ site number to that geofence. When a worker enters the zone, Suivo knows exactly which site they’re arriving at.
3. Choose your registration method
Suivo offers three flexible options to match different site types:
• Vehicle hardware (RFID) workers scan their badge in the work van. When the vehicle’s GPS tracker enters the site geofence, Suivo automatically registers everyone on board in CIAW
• Suivo App workers tap “Check in” on their smartphone. GPS verifies the location and transmits the data instantly
• Site terminal a fixed badge point at the site entrance. Workers scan their badge or Limosa QR code. Ideal for large, permanent sites with multiple teams
4. Automatic submission to RSZ
After each check-in, Suivo transmits all data via a secure connection to the RSZ in real time. No manual entry on the RSZ website, no CSV uploads, no missed registrations.
5. Live monitoring from the Netherlands
Your HR team or planner can see in the Suivo dashboard exactly who has successfully checked in (green status) and where there’s an error for example, a missing or expired Limosa number (red status). You can act immediately, before an inspector arrives on site.
| Without Automation | With Suivo |
| Manual RSZ login every morning for every worker | Automatic registration via badge, app, or sitepole |
| Easy to forget one missed day = one fine | GPS-triggered: registration happens as workers arrive |
| No visibility from the Netherlands office | Live dashboard showing all sites and all workers |
| Expired Limosa discovered only during inspection | Real-time alerts for missing or expired Limosa numbers |
| Paper L1 documents scattered across sites | All Limosa data linked centrally to employee profiles |
| Hours of admin per week | Zero manual entry on site |
Quick Compliance Checklist for Dutch Companies
Use this checklist before your team crosses the border:
| Action | Status | Owner |
| Limosa declaration submitted for all employees going to Belgium | HR | |
| L1 documents received with Limosa numbers and QR codes per employee | HR | |
| Limosa numbers entered in Suivo and linked to employee profiles | HR / Admin | |
| RSZ site number obtained from Belgian client or main contractor | Project Mgr | |
| Geofence created in Suivo with correct RSZ site number attached | Admin / IT | |
| Registration method chosen and tested (app, RFID, or terminal) | Operations | |
| HR team trained on monitoring the Suivo dashboard | HR | |
| Process for Limosa renewals defined (before expiry) | HR |
Frequently Asked Questions
Can a Dutch company register in CIAW without Limosa?
No. For foreign workers, the Limosa declaration is a prerequisite for CIAW registration. Without a valid Limosa number, the CIAW system cannot identify the worker. The Limosa declaration must be completed before the worker arrives in Belgium.
Does the Limosa declaration need to be renewed?
Yes. A Limosa declaration is valid for the period specified in the application. If a project runs longer than declared, or if a worker returns for a new assignment, a new declaration is required. Suivo can flag expiring Limosa numbers so your HR team can renew them before they lapse.
What if my worker forgets to check in one morning?
A single missed check-in constitutes a violation and can result in a fine of €600 to €6,000 for that day. This is why automation is critical GPS-triggered registration via Suivo means check-ins happen as workers arrive, without relying on individual memory.
Is the main contractor liable if my company doesn’t comply?
Yes. Under Belgian law, clients and main contractors can be held jointly liable for the non-compliance of their subcontractors. Since 2026, stricter due diligence rules in high-risk sectors (construction, cleaning, meat processing) require prime contractors to actively verify the compliance status of everyone in their supply chain.
Can I use Suivo if I only occasionally work in Belgium?
Yes. Suivo is scalable it works for a single employee on one site just as well as for full crews across multiple Belgian projects. The platform doesn’t require a long-term commitment for occasional use, making it practical for Dutch companies that work in Belgium periodically.
Does Suivo also handle time registration and payroll?
Yes. Beyond CIAW compliance, Suivo’s platform includes time registration, scheduling, and payroll integration. The same attendance data that feeds the RSZ also flows into your payroll system eliminating double data entry and ensuring every worked hour is accounted for.
Which VAT Number is Required for Checkinatwork (CIAW) in Belgium?
If you are a Dutch company expanding your operations into the Belgian market, understanding the Checkinatwork (CIAW) registration process is vital for compliance. The VAT number you need to provide depends entirely on your contract structure:
- Subcontracting for a Belgian Client: If you are performing work on behalf of a Belgian company, you must register using the Belgian company’s VAT number.
- Direct Contracts in Belgium: If you are working directly for an end-client or performing work independently, you are required to have and use your own Belgian VAT number.
Working in Belgium? Make CIAW compliance automatic.
Book a free demo and see how Suivo handles Limosa, CIAW, and attendance registration from one platform.
