AUG (Authorized User Group) Certified
IND Recognised Sponsor
Nasscom Certified
SNA Certified
Nasscom Certified
What Is Dimona?
Dimona (Déclaration Immédiate / Onmiddellijke Aangifte) is the mandatory electronic declaration that Belgian employers must submit to the National Social Security Office before an employee's first working day, and again when that employment ends. It is required for every type of employment contract, regardless of duration or sector.
Dimona isn't optional or something to file after the fact; the “IN” declaration must be submitted before the employee actually starts working, not on their first day.
Dimona at a Glance
| Attribute | Description |
|---|---|
| Purpose | Notifies the NSSO of an employee's start and end dates |
| Timing (Dimona IN) | Must be filed before the employee's first working day |
| Timing (Dimona OUT) | Must be filed no later than the day after departure |
| Required Information | Employee's Social Security Identification Number (SSIN), Joint Committee |
| Filed Via | The online Dimona service (secured or non-secured version) |
| Penalty for Non-Compliance | Criminal fines from €2,400 to €24,000, plus NSSO penalties |
Why Does It Matter?
Dimona is a hard compliance checkpoint, not a formality. Filing late, or not at all, exposes an employer to significant fines and creates a legal record gap that can complicate social security entitlements for the employee. Because it must be filed before work begins, it needs to be built into onboarding timelines rather than handled reactively.
When Is It Used?
Dimona filing is relevant whenever a company:
- Hires a new employee in Belgium, of any contract type or duration.
- Ends an employment relationship and needs to formally close out the employee's record.
- Assigns an employee to a specific Joint Committee as part of the declaration.
A UK retailer hires a store manager in Antwerp starting on the 1st of the month. Before that start date, the company (or its Belgian payroll provider) files a Dimona IN declaration, specifying the applicable Joint Committee, ensuring the employee is properly linked to Belgian social security from day one.
Common Misconceptions
No. It must be completed before the employee actually begins working, not simultaneously with their start.
No. It applies to every type of employment contract, including part-time, fixed-term, and occasional work arrangements.
No. Non-compliance can trigger criminal fines ranging from €2,400 to €24,000, plus additional NSSO penalties.
No. It works alongside the quarterly DmfA declaration, which separately reports wages and hours worked.
Dimona is a mandatory, time-sensitive declaration that Belgian employers must file before an employee starts work and after they leave. Building this into onboarding and offboarding checklists from the outset avoids significant compliance risk.
Hiring in Belgium?
We'll handle your Dimona declarations, Joint Committee assignment, and social security registration before day one.
experts@adtsolution.com
Queens towers, Delflandlaan 1, 1062 EA Amsterdam, The Netherlands
