Posting Workers to Belgium: Declaration, Pay Rules, Documents and the A1

The National Social Security Office (NSSO) runs the declaration.

Posted workers stay employed by the foreign employer. The EU rules for posted workers set the frame, and Belgium adds the declaration, the joint committees and the Social Penal Code.

Five key figures apply as of 5 November 2026.

• Act of 5 March 2002 and Royal Decree of 1 April 2007
• Limosa compulsory since 1 April 2007, filed before work starts
• 12-month exemption from Belgian social documents once declared
• Extra Belgian conditions after 12 months, six more months on a motivated notification
• A1 for employees from the NSSO

Which Belgian Rules Apply When You Post Workers to Belgium

Posting to Belgium is governed by the Act of 5 March 2002 on working, pay and employment conditions in case of posting and their monitoring and its Royal Decree of 1 April 2007, while the Limosa declaration rests on Title IV, Chapter VIII of the Programme Law (I) of 27 December 2006. Directive (EU) 2018/957 has applied in Belgium since 30 July 2020.

Directive 96/71/EC binds Belgium; employers are bound by the Belgian act. The FPS Employment, Labour and Social Dialogue (FPS) runs the single official website, the liaison office and the labour inspection; the NSSO (ONSS in French, RSZ in Dutch) runs the declaration and issues the A1 for employees.

The single official website is employment.belgium.be, as listed on Your Europe (business page, 30 September 2026). The liaison office is at Rue Ernest Blerot 1, 1070 Brussels, as of 5 November 2026. The Posting of Workers Directive sets the minimum list of host-country terms.

Prior Declaration in Belgium: Who Files, When and What It Covers

A foreign employer, or its representative, must declare employees who work temporarily or partially in Belgium and are not subject to Belgian social security through Limosa before their work in Belgium starts, as required since 1 April 2007 by the Programme Law (I) of 27 December 2006. Article 9(1)(a) of Directive 2014/67/EU sets only the EU floor, a declaration "at the latest at the commencement of the service provision".

The employer receives a Limosa-1 receipt (L1) and shows it to the Belgian client before work. Exemptions, limits per declaration and the filing steps are on the page for the Limosa declaration step by step.

Road-transport drivers are declared through IMI instead (Article 1(11)(a) of Directive (EU) 2020/1057, applying since 2 February 2022).

Rules from limosa.be, checked 5 November 2026.

Every obligation before, during and after a posting is listed in the posting compliance checklist.

Pay and Working Conditions in Belgium: Joint Committees and Sector Rules

Workers posted to Belgium are entitled to the pay and working conditions set for the joint committee (commission paritaire, paritair comité) that covers the employer's main activity, with Joint Committee 124 covering construction.

Initial assembly or installation of up to eight days is exempt from the pay rules, never in construction, mirroring Article 3(2) of Directive 96/71/EC. Article 3 of that Directive is the basis of posted worker remuneration.

Extra Conditions after 12 and 18 Months in Belgium

After 12 months of posting in Belgium, the additional Belgian working conditions apply, and a motivated notification moves that point by six months, counted from the first day of the 13th month.

Article 3(1a) of Directive 96/71/EC excludes the formalities of concluding and ending the contract and supplementary occupational pensions, and a notification is not an application. This is the labour-law clock only, and the worker stays posted; see long-term posting.

Documents and the Liaison Person in Belgium

An employer that has filed the declaration is exempt for 12 months from drawing up the Belgian social documents, but must keep the equivalent documents of its home country, provide them on request in Dutch, French or English, and keep them available for one year after the posting.

The liaison person is named in the declaration and may live in Belgium or abroad; Article 9(1)(f) of Directive 2014/67/EU likewise does not require a contact person present in the host State. The guide to documents for posted workers lists what inspectors ask for.

Labour Inspection, Sanctions and Site Registration in Belgium

The FPS Employment labour inspectorate checks posted work in Belgium, and the sanctions for a missing declaration and for a Belgian client who fails to report a missing receipt are set in Articles 182 and 183 of the Social Penal Code of 6 June 2010, as amended with effect from 1 September 2026. Fines in other host States are compared under posting penalties in other countries.

Construction sites of EUR 500,000 excluding VAT or more require daily Checkinatwork registration before work, and foreign workers can register with the L1 QR code. From 1 April 2027, IN and OUT registration becomes mandatory for works on immovable property, excluding cleaning, and for ready-mixed concrete.

Rules from the Social Penal Code and the Checkinatwork page, checked 5 November 2026.

The A1 Form from Belgium: The NSSO as Issuing Institution

An employer in Belgium obtains the A1 for an employee or civil servant it sends to another EU or EEA State or Switzerland from the National Social Security Office (NSSO), the institution named in the Commission list of A1 contact points of 22 October 2021 and on the FPS posting pages. The A1 runs on the social security clock: up to 24 months of anticipated duration under Article 12(1) of Regulation (EC) No 883/2004, provided the worker does not replace another posted person; self-employed persons fall under Article 12(2).

Today the employer informs the institution "whenever possible in advance" (Article 15(1) of Regulation (EC) No 987/2009). Each State has its own route to apply for an A1.

Issuing institution and contact, checked 5 November 2026.

Social Security Cover for Workers Coming to Belgium

A worker posted to Belgium from another EU or EEA State or Switzerland stays insured at home where Article 12 of Regulation (EC) No 883/2004 applies, and the A1 issued there binds Belgian institutions and courts until the issuing State withdraws it or declares it invalid.

Belgian courts may disregard it only for fraud, after the dialogue procedure (C-359/16 Altun, C-370/17 Vueling); C-421/23 (23 January 2025) held that procedure a compulsory precondition. Workers detached from the UK keep UK legislation for up to 24 months under Article SSC.11 of the TCA Protocol; the EU-UK derogation agreements proposed on 15 October 2026 (COM(2026) 550) are pending as of 5 November 2026. Belgium is a signatory of the telework Framework Agreement, with the NSSO as competent institution.

Rules Applying from 2 November 2028

Regulation (EU) 2026/2359 of 7 October 2026 has been in force since 1 November 2026, but its new Article 12 and the prior-notification rules apply only from 2 November 2028; until then today's rules apply, and persons sent before that date stay under the old Article 12 (Article 87b(4) of Regulation (EC) No 883/2004).

From that date the employer notifies before the activity, with an automatic acknowledgement where the A1 is not issued at once (Article 15(1), (1a) of Regulation (EC) No 987/2009). Business trips and up to three consecutive days within 30 days, except the construction work in Annex 6, are exempt from that notification (Article 15(1b)), and the prior affiliation of a person recruited to be posted rises from one to three months (Article 14(1)); the revision of Regulation 883/2004 lists every change.

The take-over of Regulation (EU) 2026/2359 by Norway, Iceland, Liechtenstein and Switzerland is pending as of 5 November 2026.

Belgium Compared with Other Posting Countries

Belgium, like France and the Netherlands, asks for the posting declaration before work starts, while Article 9(1)(a) of Directive 2014/67/EU sets only the commencement of the service as the EU limit. The posting rules by country compare 32 States.

• posting workers to France
• posting workers to the Netherlands
• posting workers to Germany

Questions on Posting to Belgium

Four questions recur on posting to Belgium.

Must every assignment to Belgium be declared in advance?

Yes for employees not subject to Belgian social security who work temporarily or partially in Belgium: the Programme Law (I) of 27 December 2006 requires a Limosa declaration before work starts; some activities are exempt.

How long can a worker be sent to Belgium?

Belgian labour law sets no end date: extra Belgian conditions apply after 12 months, or after 18 with a motivated notification, while A1 cover lasts for an anticipated duration of up to 24 months (Article 12(1) of Regulation (EC) No 883/2004).

Which body issues an A1 for a posting from Belgium?

The National Social Security Office (NSSO) issues the A1 for employees and civil servants sent from Belgium to another EU or EEA State or Switzerland, as the Commission list of A1 contact points shows.

Does a UK employer need an A1 for workers in Belgium?

A worker detached from the UK keeps UK legislation for up to 24 months under Article SSC.11 of the TCA Protocol, and the UK-issued A1 is the proof Belgian institutions accept; the Belgian declaration rules still apply.

Pending EU Changes Affecting Belgium

As of 5 November 2026, the proposed regulation on an EU e-declaration for posting (COM(2024) 531, procedure 2024/0301(COD)) is pending: the European Parliament adopted its first-reading position on 20 October 2026 and the Council's is awaited. Host States would opt in voluntarily.

Limosa remains the Belgian route; the EU e-declaration page tracks the proposal.