Posting Workers to Spain: Declaration and ITSS Inspection Guide

A Spanish labour inspector can walk onto a client site and ask for your posting file that day. Two documents decide how it goes: the A1 certificate and the Comunicación de Desplazamiento. Different authorities issue them, and inspectors read one against the other.

Which EU Regulations Govern Posting a Worker to Spain?

The Posted Workers Directive (96/71/EC and the 2018 revision)

Spain transposed both through Ley 45/1999.

• Your employee gets the pay and conditions of the applicable convenio colectivo.
• A standard posting runs 12 months.
• A motivated notification filed before month 12 stretches it to 18.
• Past that, almost all Spanish employment law applies.

The Enforcement Directive and its inspection powers

Directive 2014/67/EU, transposed by Royal Decree-Law 9/2017, created today's audit exposure.

• The ITSS can demand your documents, in Spanish, during and after the posting.
• You must name a liaison based in Spain.
• Fines issued in Spain can be enforced against you at home.

Regulation 883/2004 and social security coordination

• It decides which social security system your employee stays in.
• A posting can keep home country contributions for up to 24 months.
• The A1 is the proof. Without it, Spain can claim contributions from day one.

What Social Security Document Does a Posted Worker Need in Spain?

A1 for EU/EEA senders vs. Certificate of Coverage for treaty countries

• EU, EEA or Switzerland: apply for the A1 certificate at home.
• Treaty countries such as the US, Japan, Brazil or Morocco: a Certificate of Coverage instead.
• No treaty: register the employee in Spanish social security from day one.

How the A1 fits into a posting (not an ICT transfer)

• A posting keeps your employee on the home contract and home payroll.
• An ICT permit is an immigration route for non-EU nationals moving inside your group, and it answers social security differently.
• Decide the route first. The paperwork follows from it.

Where to find A1 issuing authorities and timelines

• The A1 comes from the sending country, not from Spain.
• Apply before departure. Retroactive A1s are possible, but they read badly in an inspection.
• Certificates of Coverage can take months, so start early.

For the full breakdown of A1 certificates, Certificates of Coverage, and issuing authorities by country, see our guide to Spain ICT social security.

How Does the A1 Pair With the Spanish Posting Declaration?

Why the A1 alone doesn't satisfy the labour authority

Two authorities, two files. The A1 answers social security; the posted worker communication answers labour law. A flawless A1 will not stop a fine for a missing declaration.

Sequencing: A1 in hand before the declaration is filed

• Start the A1 as soon as the assignment is approved.
• File the declaration before the first working day.
• If the A1 is still pending, file anyway and keep the application receipt. A late declaration is a serious infringement; a pending A1 is not.

Keeping both documents assignment-ready

• One digital file per posted worker, reachable in minutes.
• Declaration receipt, A1, contract, payslips, payment proof, time records.
• Spanish translations ready in advance, or the region's co-official language.

What Must a Spanish Posting Declaration Contain?

Worker, employer, and host-company details

• Your company identification and tax details.
• Personal and professional details of each posted employee.
• The Spanish company or companies receiving the service.

Assignment duration and service description

• Start date and expected duration.
• Workplace address in Spain.
• What the service actually is. Vague wording invites follow-up questions.

The designated liaison and service address in Spain

• A person or entity in Spain who receives official documents and notices.
• A contact able to represent you with worker representatives.
• A valid Spanish postal address. A colleague who left months ago is a finding waiting to happen.

Where and When Is the Posting Declaration Filed?

The regional labour authority as the filing destination

• File with the autonomous community where the work happens, through the Ministry's Ley 45 portal.
• Ceuta and Melilla go to the Government Delegations instead.
• Work across three regions means three separate filings.

The "before activity begins" deadline

• File before work starts, whatever the length of the assignment.
• Certain postings of eight days or less are exempt. Never for temporary work agencies.
• The exemption covers the filing only. Equal treatment and A1 duties still apply from day one.

Provincial filing differences across autonomous communities

• Several communities route filings to provincial or territorial labour offices.
• Some treat your first filing as a registration request.
• Catalonia, the Basque Country, Galicia and Valencia may want co-official language translations.
• Construction adds registration in the REA.

How Do the A1 and Posting Declaration Work Together in an ITSS Inspection?

What inspectors cross-check between the two documents

• Names, dates and employer details on the A1 against the declaration.
• The declared service against what the team is doing on site.
• Whether the sending company genuinely trades at home. Joint Spain and Portugal operations target exactly this.

Records you must retain and for how long

• During the posting: at the workplace or digital, for immediate consultation.
• After it ends: produced on request by the labour inspection.
• No single retention period exists in law. Infringements can be pursued for three years, so treat three years as your floor.

Common documentation gaps that trigger findings

• Declaration filed a day or two after work started.
• Liaison named on the form but no longer contactable.
• Assignment past 12 months with no motivated notification.
• Payslips available in the home language only.
• Per diems counted towards the collective agreement minimum.

What Are the Penalties for Missing or Incorrect Documentation?

The LISOS sanction tiers (minor, serious, very serious)

Fines apply per infringement under the LISOS, and one visit can produce several.

Joint liability between sending and host company

• Your Spanish client is not a bystander. In subcontracting chains, liability is usually shared.
• Expect hosts to ask for your declaration receipt and A1 copies before mobilisation.

Downstream impact on future filings and audits

• A sanction record raises your odds of a repeat inspection.
• Findings resurface when the same entity files immigration applications later.
• Large Spanish clients screen suppliers for open sanctions.

How Can HR Standardise Posting Compliance Across Multiple EU Markets?

Building a repeatable pre-departure checklist

• Confirm the route: posting, ICT or local hire.
• Apply for the A1 or Certificate of Coverage.
• Check pay against the convenio colectivo.
• Appoint the liaison and confirm the Spanish address.
• File, save the receipt, brief the on-site manager.

Centralised tracking for A1s and declarations

• One record per assignment, holding both document numbers and both end dates.
• An alert at month 10, so the 18-month extension is never missed.
• Map each market separately. The Netherlands notification works nothing like the Spanish one.

Spreadsheets cope with roughly 20 live assignments. After that they fail quietly.

When to bring in local representation

• You have no entity or reliable contact in the region.
• Postings span several communities, or run past 12 months.
• An inspection has already opened.

Jobbatical handles filings, liaison and records for posting workers to Spain and across the EU, so your team tracks assignments instead of chasing forms. Book a demo.

Before the next Spanish assignment is signed off, ask one question: could you produce the declaration receipt and the A1 within an hour?

Disclaimer: Immigration rules change quite frequently; please verify with official sources or contact us for the latest info before making any decisions.