Your social security cover during your posting

The world is your workplace, but what about your social security during your posting? The context of your posting determines whether you are covered by the Belgian social security system (via the NSSO) or the Overseas Social Security system (OSS).

Posting to the Belgian social security system

Posting means that you, as a Belgian employee, are temporarily posted abroad by your Belgian employer and remain subject to the Belgian social security system. The posting is temporary. The conditions are checked by the NSSO.

A post is possible to the Member States of the EEA, Switzerland, the United Kingdom and countries with which Belgium has concluded a bilateral social security agreement (also known as treaty countries).

Please note that the agreements with the treaty countries may vary depending on the type of social security (e.g. pension, health insurance, etc.).

In countries outside these agreements, you cannot claim Belgian social security. In this case, you can choose whether you want to join the OSS.

Posting to the Overseas Social Security System

The OSS ensures that, as a posted worker, you retain reliable social protection even in countries with a limited social security system and that the entitlements you have acquired are taken into account when you return to Belgium.

Read two frequently asked questions on the subject of 'posting' in the OSS system.

Can an employee affiliated to the OSS be posted to an EEA Member State, Switzerland or the United Kingdom?

Yes, this is possible. Employees who are affiliated with the OSS can be temporarily posted from their foreign office to a country within the EEA, Switzerland or the United Kingdom. The prerequisite is that an A1 certificate is issued. Please apply for this certificate at overseas@onss.fgov.be. This posting is limited to a maximum of six months. During this period, OSS coverage remains in force as long as the contributions are paid. Posting to Belgium is not possible in this case.

Can a Belgian employer affiliate their workers who are on the Belgian payroll to the OSS if they work outside the EEA, Switzerland and the United Kingdom?

This is possible. All information and the application form can be found on the Forms and Online Requests page. Insurance cover remains in force as long as contributions are paid.

Various scenarios

Scenario	System	Conditions	Maximum duration
Posting to an EEA Member State/Switzerland/United Kingdom - from Belgium	Belgian social security (via NSSO)	assessed by the NSSO + A1-certificate	in accordance with the posting rules
Posting outside the EEA/Switzerland/United Kingdom to a country with a bilateral social security agreement - from Belgium	You have the choice: Belgian social security (via NSSO) or OSS	assessed by the NSSO + A1-certificate voluntary affiliation to the OSS + contribution payment	in accordance with the posting rules no maximum duration
Posting outside the EEA/Switzerland/United Kingdom to a country without a bilateral social security agreement	OSS	Voluntary membership of the OSS + contribution payment	no maximum duration
Posting of an OSS member from an overseas location to an EEA member state/Switzerland/the United Kingdom (but not to Belgium)	OSS	Membership of the OSS + A1-certificate	maximum 6 months

Any further questions?

Please contact Frontline.

Would you like to share your travel experiences?

Are you an expat or do you know someone with an inspiring experience abroad? Please don't hesitate to contact us at overseas-expat@onssrszlss.fgov.be. And who knows, you might inspire future expats with your story.