Spain has no official “part-time autónomo” category. Register to freelance even one hour a week and you pay full Social Security contributions and file the same quarterly returns as someone billing full-time. The only legal route to lower costs is pluriactividad — being employed and self-employed simultaneously. This guide covers what the law says, how pluriactividad works under the 2023 reform rules still in force in 2026, what it costs, and how to register without losing the €88.64 tarifa plana. Sits alongside the autónomo guide, the registration walk-through, and the full guide to registering as a freelancer.
Quick answer
No part-time category exists: one hour a week or 40 hours a week, registration is identical. Same RETA cuota, same quarterly filings, same obligations.
Minimum RETA cuota in 2026: €205.88/month (lowest declared-income bracket). New registrants pay the tarifa plana at €88.64/month for the first 12 months.
If you are also an employee (pluriactividad): after the tax year closes, TGSS refunds the excess if your combined Social Security contributions (employer SS + RETA) exceed 50% of the annual maximum contribution base. This is a year-end refund, not a monthly discount.
Check your employment contract first: exclusivity or non-compete clauses can restrict outside self-employment. Breaching one can be grounds for dismissal.
Registration time: about 30 minutes online once your digital certificate or Cl@ve PIN is active.
What “part-time self-employed” means legally
Spanish law (Ley 20/2007 del Estatuto del Trabajo Autónomo) acknowledges the concept of part-time self-employment but never turned it into a workable legal category. RETA, the Social Security regime for freelancers, charges contributions based on declared net income — not hours worked. A designer billing 5 hours a month and a consultant billing 50 register identically and face the same obligations.
The practical consequence: the minimum RETA cuota applies from day one regardless of revenue. If your freelance income does not cover the cuota plus the cost of tax filings, the numbers do not work. Estimate your income honestly before registering.
The one meaningful exception is pluriactividad — working as an employee and as autónomo at the same time. That regime is covered below.
Before you register: check your employment contract
If you are currently employed, read your contract before registering as autónomo. Many employment contracts include exclusivity or non-compete clauses that restrict outside self-employment. Breaching one can be grounds for dismissal.
Once confirmed there is no obstacle, you can proceed to registration.
How to register and your basic obligations
Registration is identical to full-time autónomo registration. For the complete step-by-step process, see the guide to registering as a freelancer. You need:
Valid DNI, NIE, or passport.
Digital certificate (FNMT) or Cl@ve PIN for online filing.
Your IAE epígrafe (activity code) — the AEAT website has a search tool.
A Spanish bank account for RETA direct debit.
Your address in Spain for the census registration.
Steps:
File Modelo 036 at AEAT (census registration and activity declaration). Do this first, before the TGSS step.
Register with RETA at the TGSS Sede Electrónica on the same day. Your RETA start date must match or follow your AEAT alta date.
Enrol in DEHú (electronic notifications) at AEAT to receive any inspection notices or letters digitally. Missing a paper notice is not an accepted excuse for non-response.
Set your quarterly filing calendar: Modelo 303 and 130 are due by 20 April, 20 July, 20 October, and 30 January.
From that point your obligations are the same as any autónomo:
Monthly RETA cuota by direct debit (or tarifa plana in year one).
Quarterly Modelo 303 (IVA declaration) if your activity is subject to IVA.
Quarterly Modelo 130 (IRPF advance, 20% of net freelance profit).
Annual Modelo 390 (IVA summary, due January).
Annual Modelo 100 (personal IRPF return, filed April-June): combines salary and freelance income if you are also employed.
Maintain a legible record of all income and expenses.
The “pluriactividad” regime: combining employment and self-employment
Pluriactividad means you are registered both as an employee (paying Social Security through your employer) and as autónomo (paying RETA cuota). Both contribution streams run at the same time.
How it works in 2026:
The 2023 income-based contribution reform removed the old upfront monthly reductions for pluriactividad. The mechanism is now a year-end refund:
You pay the full RETA cuota based on your declared income band throughout the year.
Your employer pays employer Social Security on your salary throughout the year.
After the tax year closes, TGSS calculates whether your combined SS contributions (employer SS + your RETA cuota) exceed 50% of the maximum contribution base for the year.
If they do, TGSS refunds the excess — up to 50% of your RETA contributions paid that year.
The refund is applied automatically by TGSS; you do not need to file a separate claim.
To qualify:
You must be registered in both the general Social Security regime (as an employee) and RETA (as autónomo) for the same period.
The combined contributions must exceed 50% of the annual maximum contribution base.
The calculation uses contributions from both regimes in the same calendar year.
What pluriactividad does not change:
Your quarterly IVA and IRPF filing obligations as autónomo remain unchanged.
Your employer’s HR obligations toward you remain unchanged.
The tarifa plana still applies to your RETA cuota if you are a first-time autónomo.
Income from both employment and freelancing is combined for your annual Modelo 100 IRPF return.
The tarifa plana and the pluriactividad refund can both apply in the same year if you are a first-time autónomo who is also employed.
Cost and cuotas in 2026
Cuotas are based on declared net income, not hours. The 2026 table is frozen at 2025 levels with the MEI surcharge at 0.9%. Full table in autónomo costs.
Key figures:
Tarifa plana for new autónomos: €88.64/month for the first 12 months (€80 base + 0.9% MEI, RDL 16/2025).
Minimum RETA cuota (lowest income bracket, net income under €670/month): €205.88/month.
Maximum RETA cuota (highest income bracket, net income over €6,000/month): €607.31/month.
MEI surcharge: 0.9% added to all cuotas in 2026 (frozen at 2025 level).
Additional recurring costs to budget:
Gestoría for quarterly filings: €25-60/month, or one-off fees of €40-80/quarter if you self-file with support.
Invoicing software or Verifactu-compliant tool: €0-20/month (renn has a free tier).
Annual IRPF return (Modelo 100): €49-120 if outsourced.
If you are also an employee, your salary and freelance income are added together for IRPF. This can push you into a higher bracket. Adjust your Modelo 130 payments upward if combined income exceeds €20,200 to avoid a large year-end bill.
Deductible expenses are the same as full-time autónomos:
Dedicated workspace costs (home office: up to 30% of the designated area’s expenses).
Mobile phone and internet proportional to business use.
Professional subscriptions, tools, and software.
Training and course fees related to the activity.
Travel expenses with documentary evidence.
RETA cuota (Social Security contribution) is fully deductible as a professional expense.
Keep separate accounting records for employment and freelance income. Mixing them creates reconciliation problems on Modelo 100.
Common mistakes
Using Modelo 037 for registration: Modelo 037 was abolished in February 2025. All census procedures (alta, modification, baja) now use Modelo 036 only.
Not checking the employment contract: exclusivity or non-compete clauses can prohibit outside self-employment. Always check before filing.
Registering at TGSS before AEAT: the RETA start date must match or follow the AEAT alta date. Reversing the order creates an administrative misalignment that takes time to correct.
Using the old tarifa plana rate: the correct figure is €88.64/month, not €87.6. The increase took effect under RDL 16/2025.
Not enrolling in DEHú: AEAT sends all official correspondence electronically to registered autónomos. Missing a notice because you did not check DEHú is not an accepted excuse.
Treating pluriactividad as a monthly discount: it is a year-end refund from TGSS, not a reduction in your monthly cuota. Budget the full RETA cuota every month.
Under-reporting combined income on Modelo 130: if employment plus freelance income exceeds €20,200, increase your quarterly IRPF advance payments to avoid a large settlement at Modelo 100 time.
Practical checklist to get started
Read your employment contract for exclusivity or non-compete clauses.
Obtain a digital certificate (FNMT) or activate Cl@ve PIN if you do not have one.
Choose your IAE epígrafe on the AEAT website activity search tool.
File Modelo 036 at AEAT (census registration, activity declaration, IVA regime election). Full steps in the freelancer registration guide.
Register with RETA at TGSS Sede Electrónica on the same day as your AEAT alta.
Enrol in DEHú (AEAT electronic notifications).
Open a Spanish bank account for RETA direct debit if you do not have one.
Set quarterly filing calendar reminders: 20 April, 20 July, 20 October, 30 January.
Start using Verifactu-compliant invoicing software from day one.
FAQ
Can I work as autónomo for just a few hours a week? Yes. There is no minimum hours threshold. You register, pay the cuota, and file quarterly returns regardless of how few hours you bill.
Can I be autónomo while on a student visa? No. Student visas do not authorise self-employment. You need a residency permit or a work authorisation that covers self-employment. Detail in can a foreigner register as autónomo.
What happens if I stop freelancing after a few months? File a baja at RETA to cancel your Social Security registration and file Modelo 036 as a deregistration at AEAT. Detail in how to deregister as autónomo.
Do I still pay the full cuota if I earn nothing in a month? Yes, unless you are on tarifa plana (€88.64/month). The cuota is monthly regardless of that month’s income. You can adjust your income band up to six times per year if earnings change.
Can I have the tarifa plana and the pluriactividad refund at the same time? Yes. The tarifa plana applies to your RETA cuota as a first-time autónomo. The pluriactividad refund applies to the combined total of employer SS and RETA contributions. Both can apply in the same year.
Is a gestoría required? Not legally. But quarterly filings and the annual Modelo 100 take time, especially when combining employment and freelance income. Many part-time autónomos use a gestoría for the first year. More on what gestors do at what is a gestor.
Bottom line
Working part-time as autónomo is legal and common. The law does not give you a discount for fewer hours. What it does offer: tarifa plana at €88.64/month for the first year, a year-end Social Security refund if you are also employed under pluriactividad, and the same deductions as full-time freelancers. Check your employment contract before filing, submit Modelo 036 at AEAT before RETA on the same day, and enrol in DEHú from day one. If you would rather not manage the paperwork, renn handles autónomo registration end-to-end and keeps your TGSS status clean.
