Registering as autónomo in Spain: tax and Social Security steps

The tax procedures in this guide concern the AEAT and Spain’s common tax regime. It does not cover Basque or Navarre tax procedures, Canary Islands IGIC or Ceuta and Melilla IPSI. Social Security rules are examined separately.

What do I need to register as autónomo in Spain?

For an individual activity covered by RETA, coordinate tax registration using modelo 036 with Social Security registration through Importass. These are separate procedures: confirmation from one authority does not prove registration with the other. Prepare the details together so you can check the activity, dates and obligations before submitting.

This guide covers the general individual case, not special procedures for immigration, family collaborators, agricultural workers, company owners or alternative professional mutual schemes. First establish whether your activity requires RETA. Low earnings are not an automatic exemption from Spain’s self-employed Social Security scheme.

Prepare the information before opening the forms

• Your identification and Social Security number. Check the identification or representation methods accepted by each service; do not assume someone else can submit without the required authority.
• A description of every activity: what you sell or provide, to whom and from where. Use it to identify the appropriate IAE tax headings and CNAE activity codes.
• Tax and activity addresses, planned start date and a timeline of purchases, payments, assignments and any work already done.
• Estimated annual net earnings for Social Security, contribution base, any applicable reduction and the collaborating mutual insurer, or mutua. Turnover is not net earnings.
• The bank account for contributions. If it belongs to someone else, Importass requires the account holder’s identification and authorisation.
• Transactions that may affect your obligations: goods or services, consumer or business customers, international transactions, employees or rent subject to withholding.

IAE and CNAE are different classifications. Copying a code from a similar business is not enough, and a heading does not determine every tax obligation. Describe both activities if you have two, before choosing the relevant sections of modelo 036.

Official source: Importass: information required for registration. Additional details may be required. Checked 26 September 2026; source in Spanish.

Submit modelo 036 before the activity starts for tax purposes

Modelo 036 notifies the Spanish Tax Agency of the start of the activity and its tax obligations. The relevant date is not necessarily your first invoice. Article 9.4 of the census regulations also includes purchases, payments, supplies, services, receipts and hiring staff for the activity. Preparatory expenditure can matter before you have a customer.

Use the official 036 service and check identification, activity, addresses, date and the applicable tax sections before submitting. Censos WEB assists with specified procedures for individuals; it does not cover every transaction or amendment. Save the submission receipt, not just an unsubmitted draft.

Official access: Spanish Tax Agency: modelo 036 and tax registration services. Modelo 037 was abolished on 3 February 2025; its simplified functions are now handled through 036.

Rule on commencement: RD 1065/2007, article 9.4. Checked 26 September 2026.

Apply for RETA before starting work

Importass allows an application up to 60 days before starting. If you have already begun, you must still notify registration, but it is late. Do not alter the actual date to make an application look timely, or assume a new confirmation settles an earlier uncovered period.

Check the tax authority, IAE, CNAE, address and date, then estimated earnings, contribution base, applicable benefits, mutua and bank account. If several activities bring you within RETA, there is one registration but all activities and subsequent changes must be reported. Do not apply for a second RETA registration merely to add another activity.

Source: RD 84/1996, article 46. Multiple activities under one RETA registration and the effects of late registration.

Base the dates on what happened, not just the first invoice

You can prepare both procedures together. However, “Tax Agency first, RETA second” is not a legal rule that settles every case. Each authority applies its own commencement criteria. Where dates differ, establish why and retain supporting facts; simply making them identical can conceal an incorrect date.

Check both sets of documents

Importass lets you consult and download PDF records of registration, deregistration and amendments. These establish what was processed by Social Security, not by the Tax Agency. If someone submits on your behalf, ask for each receipt and confirmation of anything outstanding. Submission, acceptance and checking are different steps.

Official service: Importass: evidence of registration or deregistration. Includes documents recording amendments.

Check the reduced contribution before submitting

The tarifa plana is a contribution reduction with eligibility conditions, not a guaranteed benefit for every new business. Article 38 ter requires an application when registering and, where a second period applies, before that period begins. Check previous registrations, earlier reductions and the conditions for your category. Regional grants have separate applications; they are not the same as the national reduction.

Source: Self-Employed Workers’ Statute: article 38 ter. Eligibility, application and duration. Checked 26 September 2026.

Separate Social Security contributions, taxes and adviser fees

The monthly contribution is not the cost of submitting a form or hiring an adviser. It depends on contribution rules, estimated earnings, the selected base and applicable benefits. VAT and income tax are separate obligations. Budget for each item and check the current official calculation instead of treating an old minimum or promotional saving as a universal amount.

Prepare your first invoice after registration

Check the required particulars and the transaction’s VAT treatment, any exemption and applicable withholding. A business customer does not automatically mean the same withholding for every activity. For a customer abroad, their country and business or consumer status are not enough without identifying the transaction.

Further reading in Spanish: what an invoice must contain. Keep your registration receipts and records supporting earlier business expenses too.

List the returns you actually need to file and the first period each covers. VAT, payments on account, withholding returns and information returns are not identical for everyone. One invoice with withholding does not automatically remove your other obligations.

If you work with customers abroad, read how to invoice EU and foreign clients from Spain before choosing the invoice treatment.

If you plan to hire, use the employee cost calculator and first-hire guide to prepare a separate employment budget and check the hiring steps. An autónomo registration alone does not complete those procedures.

Locate an error before trying to correct it

Compare the submitted detail, the correct detail and supporting evidence. An address, an unreported activity and a disputed RETA date may need different procedures. A second registration does not simply replace the first. If you have received a notice or debt claim, or need a retrospective change, check the specific procedure and deadline.

If you want help with registration

Finlai publishes this guide. Its plans and services advertise autónomo registration and a tax adviser. Confirm who submits each application, the authorisation required and which records you will receive. This guide does not guarantee same-day completion or a two-hour service. Finlai does not serve the Basque Country or Navarra.