Self-Employed in Spain for Foreigners: A Complete Guide to Registration, Social Security and Quarterly Tax Forms

Moving to Spain to work for yourself -whether you’re a digital nomad, a freelancer from another EU country, or a professional from outside Europe looking to settle here- means getting your head around a tax and administrative system that can look like a maze at first glance. The good news is that once you know the steps, the process is entirely manageable. This guide walks through everything a foreigner needs in 2026 to become self-employed (an “autónomo”) in Spain: from the first identification document to the tax returns you’ll file every quarter.

Step one: getting your NIE

Before you can issue invoices, open a bank account under a professional name, or register with any Spanish authority, you need an NIE (Foreigner Identification Number). It’s the number that identifies any foreign national for tax purposes in Spain, and it shows up in nearly every procedure: contracts, leases, tax registrations, invoices. Citizens of the European Union and the European Economic Area can generally apply for it fairly quickly, by presenting their passport or national ID card at a police station or at the Spanish consulate in their home country. For non-EU nationals, the NIE usually comes attached to a self-employment residence and work permit, a longer process that’s best started months in advance: without a valid work authorization, you cannot legally operate as self-employed, even if you already hold an NIE for other reasons (owning a property, for instance). Once you have it, it’s also worth registering with the local town hall (the “padrón”), since that certificate is frequently requested in later procedures.

Tax registration and Social Security registration: the two essential steps

With your NIE in hand, there are two registrations every self-employed person must complete before issuing their first invoice. The first is tax registration with the AEAT (Spain’s Tax Agency), using Form 036 or its simplified version, Form 037. On this form you declare the economic activity you’ll carry out (via an activity code), whether you’ll be taxed under the general VAT regime or a special one, and the date you start operating. It’s a free procedure, and in practice it’s what determines which tax forms you’ll need to file afterwards.

The second registration is with the RETA (the Special Social Security Regime for Self-Employed Workers), the branch of Social Security that covers those working for themselves and grants access to public healthcare, sick leave and retirement benefits. Since the reform that came into force a few years ago, the monthly RETA contribution is no longer a flat amount for everyone: it’s calculated in brackets based on your estimated actual net income, which can be revised during the year and is reconciled at year-end if your forecast didn’t match reality. The lower your estimated income, the lower your contribution, and there are significant discounts for those registering for the first time (the well-known “flat rate”), applicable during the first months of activity. It’s worth estimating your income realistically, since an unrealistically low forecast can trigger a reconciliation payment with a surcharge.

Which forms you’ll file each quarter

Once you’re up and running, self-employment in Spain comes with recurring tax obligations, almost always on a quarterly basis. The most common are Form 130, an advance payment toward personal income tax (IRPF) calculated on the quarter’s profit; and Form 303, the VAT return, where you settle the difference between the VAT charged on your invoices and the VAT paid on your expenses. If you invoice clients in other EU countries, you may also need Form 349, which reports those intra-community transactions. Annually, these are joined by, among others, Form 390 (the annual VAT summary), Form 347 (transactions with third parties above a certain annual amount), and, as part of your income tax return, Form 100, where all your income for the year is reported, including income earned outside Spain if you’re a tax resident here. Each form has its own calendar and its own logic, and choosing the wrong VAT regime at the registration stage can complicate everything that follows.

This whole journey -NIE, tax registration, RETA, quarterly forms- is entirely manageable, but it benefits enormously from guidance that understands both the Spanish system and the questions that typically arise for newcomers. At Zythos Business we help self-employed professionals and small businesses, including those from abroad, take these steps without surprises: from choosing the right tax regime to filing each form on time, so your time goes into your business, not your paperwork.