Starting a business in Spain means choosing a legal structure, getting a NIE, registering with the tax office, and joining social security. Most solo founders choose between autónomo (self-employed) and Sociedad Limitada (SL, limited company). This guide walks the full path in order, with the 2026 numbers, the right forms, and the common mistakes.
Madrid, Barcelona, and Valencia are established European startup hubs. The cost of living is lower than London, Paris, or Amsterdam. The Beckham Law offers a 24% flat income tax rate for qualifying inbound workers for up to six years. Ley 28/2022 (Startup Law) cut corporate tax to 15% for certified innovative startups and simplified incorporation. The Digital Nomad Visa opens a path for remote workers from outside the EU.
For most founders the administrative path is the same regardless of nationality: NIE, structure choice, tax registration, social security. The sections below take each step in order.
Two documents unlock everything: the NIE and, for non-EU citizens, the right immigration authorization.
The NIE (Número de Identificación de Extranjero) is your Spanish tax and administrative ID. You need it to open a bank account, sign a lease, register a business, and pay taxes. Without it, nothing moves.
Apply with Form EX-15 at a Spanish consulate in your home country before you arrive, or with Form EX-18 at a Comisaría de Policía once in Spain. Bring your passport, the form, and the Modelo 790-012 fee slip (~€10-12). State the reason as "to start a business". Allow 2-6 weeks for an appointment in Madrid, Barcelona, or Valencia.
On residency and immigration:
This is the most consequential early decision. It affects your tax bill, personal liability, setup cost, and administrative workload.
Autónomo is the self-employed route. You and your business are the same legal entity. Setup takes a few days and costs almost nothing. The downside: unlimited personal liability. If the business owes money, creditors can pursue your personal assets. Tax is progressive IRPF (19% to 47% depending on income).
SL is a limited company. The SL is a separate legal entity. Your personal assets are protected from company liabilities. Corporate tax is 25% standard (23% for qualifying SMEs; 15% for newly created companies and certified innovative startups under Ley 28/2022). Setup takes 4-6 weeks and costs €600-€1,500 in notary and registry fees.
Quick comparison:
The €60,000 threshold is a rough guide. The real calculation depends on deductible expenses, whether you have co-founders, and whether you want the liability shield from day one. Full comparison: autónomo vs employee 2026 and autónomo to SL: when to switch.
Once the structure is decided, two registrations make you official: AEAT (tax office) and Seguridad Social.
Step 1: AEAT census filing (Modelo 036). File Modelo 036 before your activity start date. This tells the tax agency who you are, what you do (IAE epígrafe), your IVA regime, and whether you need to register for VIES if you invoice EU clients. Modelo 037 was abolished on 9 February 2025 (Orden HAC/1526/2024). Every alta now uses Modelo 036.
Picking the right IAE epígrafe matters. It determines your IVA treatment, your IRPF withholding rate, and whether your profession is regulated. If you get it wrong, Hacienda can reclassify it retroactively. File a Modelo 036 modificación to correct it, but better to pick correctly the first time.
Step 2: RETA alta (Modelo TA.0521). Register in the Régimen Especial de Trabajadores Autónomos via the Importass portal (portal.seg-social.gob.es). File up to 60 days before your activity start date and no later than the start day itself. The alta date is when your monthly cuota clock starts. Order matters: 036 first, RETA second, or on the same day. Filing RETA before 036 creates a date conflict and can cost you the tarifa plana.
For an SL, the director with controlling ownership (≥25% of shares, or ≥50% in a family-owned company) must also alta in RETA as an autónomo societario. File within 30 days of Registro Mercantil inscription. Missing this triggers TGSS fines and back-cuotas.
RETA contributions in 2026 are calculated on real net profit through 15 brackets:
You can change your bracket up to six times a year via Importass. At year-end TGSS regularises against your actual Renta declaration. If you underpaid, you owe the difference; if you overpaid, you get a refund. Full breakdown: social security for autónomos 2026.
Once you are registered, four recurring obligations apply to most autónomos:
SLs use different forms: Modelo 200 (Impuesto sobre Sociedades, filed in July), Modelo 202 (quarterly corporate tax advances above certain revenue thresholds), Modelo 303 for IVA, and annual accounts filed at the Registro Mercantil.
Spain is rolling out Verifactu, a mandatory certified invoicing system that creates a tamper-proof QR-coded record of every invoice you issue and sends it to AEAT in real time.
What this means in practice: you can no longer use a Word template, a basic spreadsheet, or non-certified software. Your invoicing tool must be AEAT-certified, generate the QR code and submission hash automatically, and ensure invoices cannot be secretly modified or deleted. Choose a Verifactu-compliant tool from day one. renn's invoicing is built to this standard: getrenn.com/electronic-invoicing.
renn handles autónomo registration (Modelo 036 with the right IAE epígrafe, RETA alta, tarifa plana election, mutua selection, regional cuota cero application) and SL incorporation (NIE coordination, name reservation, notary deed, Registro Mercantil, provisional and final NIF, full Modelo 036 setup). After registration, renn keeps the quarterly filings, RETA adjustments, and Verifactu-compliant invoicing running. Real accountants on the file, the platform handling the paperwork rhythm.
Start as autónomo: getrenn.com/set-up-as-autonomo-online. Register an SL: getrenn.com/limited-company-registration.
