To make a Dimona declaration in Strobbo, you need the person's National Insurance number. There are of course several statutes and each has its own regulation.

Students without National Insurance number

What should you do if there's a student without a Belgian National Insurance number in your company?

Make the first Dimona for this student on the Social Security website. Here you'll receive the BIS-number. The BIS-number resembles the National Insurcance number but the month of birth is increased with 20 or 40.

Extras without National Insurance number

What should you do if there's an extra without a Belgian National Insurance number in your company?

The person should go to the city Hall. Here he/she will receive a BIS-number. The BIS-number resembles the National Insurcance number but the month of birth is increased with 20 or 40.

Attention: this is only applies to employees who will stay in Belgium for less than 3 months.

Flexis without National Insurance number
In theory a flexi-employee should already be employed full-time in a different company. This means he/she already owns a BIS-number or National Insurance number.