Here is exactly how to register as autónomo with Social Security in Spain using Importass. You will see the steps, what data you must have ready, timing rules, how to choose your contribution base, and how the €88 flat rate works in 2026. Since 2018, autónomos must complete these trámites online, so you will need Cl@ve or a digital certificate.
Q&A
Do I register first with AEAT or Social Security?
You can do both the same day. Practically, get your AEAT alta first so you already have your IAE code ready.
Can I file the alta in advance?
Yes. You can file your Social Security alta up to 60 days before your start date.
What login do I need?
Cl@ve or a digital certificate. Both work in Importass.
What if I start working before filing?
You can still file, but it is considered out of term and may trigger surcharges or back payments.
When is the Social Security payment charged?
On the last business day of each month by direct debit.
Is the €88 flat rate for everyone?
It applies to new autónomos who meet eligibility rules. If your net income stays below the SMI, you can extend it for 12 more months.
How to register as autónomo with Social Security
- Prerequisite: have your AEAT alta and IAE epígrafe ready.
- Go to Importass and choose "Alta en trabajo autónomo".
- Identify yourself with Cl@ve or digital certificate.
- Fill the form: IAE and CNAE, start date, address, estimated monthly net income, contribution base, mutua, and bank account.
- Submit on or before day one. Download the receipt and keep it.
- See our YouTube video tutorial for a free walkthrough.
Read the full self-employed registration guide for context on both AEAT and Social Security steps.
Step by step: RETA registration in Importass
1. Access Importass
Go to the platform and choose "Altas, bajas y modificaciones", then select "Alta en trabajo autónomo."
2. Identify yourself
Use your Cl@ve credentials or a digital certificate.
3. Have this ready
• IAE epígrafe from your AEAT registration
• CNAE code
• Start date and business address
• Estimate of your average monthly net income for the year
• Choice of mutua (the insurer that manages benefits like sick leave)
• IBAN for direct debit
4. Complete the form sections
(see screenshots below)
- Last step: enter your IBAN for direct debit and review all your information.
Submit and save proof. You will get a confirmation. Your vida laboral will later show the alta date.
Deadlines and timing to avoid surcharges
- Before you start. You must be in RETA on or before your first day of activity.
- 60-day advance window. You can file early to avoid last-minute issues.
- Late filing. Allowed, but considered out of term — may trigger recargos.
- Coordinate with AEAT. Many people pre-file both the AEAT alta and Social Security alta on the same day.
Choosing your contribution base under the 2026 real-income system
Spain uses real-income bands. You estimate your average monthly net income and choose a base inside the corresponding band. Your monthly cuota depends on that base.
- There are 15 bands from low to high income.
- You can change your base up to six times per year to track your actual income.
- A small MEI surcharge applies to all workers for system sustainability.
- A higher base means higher protection for sick leave, maternity or paternity, and future pension.
Rule of thumb: pick a base that fits your income, then adjust during the year if your income changes significantly.
Flat rate €88 and pluriactividad
Tarifa plana €88.
- New autónomos pay €88 per month for the first 12 months.
- If your net income stays below the SMI, you can get 12 extra months at €88.
- You must not have used tarifa plana recently, and you cannot have debts with AEAT or TGSS.
Pluriactividad.
If you are also an employee, you are in pluriactividad. Your reductions differ from tarifa plana. In some cases, pluriactividad gives a better result than the flat rate. Compare both or ask an expert if unsure.
Mutua and coverages you must choose
Mutua is the collaborating insurer that handles your benefits. You must select one during alta.
- Common contingencies. Always included.
- Accidents at work and occupational disease. Required for some activities; advisable for higher-risk jobs.
- Cese de actividad. Protection similar to unemployment for autónomos, if conditions are met.
Pick a mutua with good digital claims handling. You can request a change later if needed.
Paying your Social Security: when and how
- Charge date. The cuota is charged by direct debit on the last business day of each month, paid in arrears.
- Visibility. From around the 26th of each month, you can view the upcoming charge in your online area.
- Bank changes. If you change IBAN mid-month, it may not apply until the following month. Do it early.
- Missed payment. Keep enough balance on charge date. A failed charge can trigger recargos if not resolved quickly.
After your alta: what to check next
- Download the alta proof and keep it alongside your AEAT alta.
- Check your vida laboral to confirm your registration dates.
- Review your contribution base regularly. If your income changes, request an adjustment — up to six times per year.
- Watch your electronic notifications. TGSS can send regularization notices if your declared income and chosen base diverge significantly.
Common mistakes that delay or invalidate your alta
- Filing after you started working. File on or before day one.
- Choosing a CNAE or IAE that does not match your actual activity.
- Forgetting to select a mutua — the form will block submission.
- Estimating income unrealistically, then being surprised by year-end regularization.
- Missing the month-end charge due to low account balance.
Less admin: renn can pre-check your IAE and CNAE, estimate your cuota, monitor your income vs. base through the year, and flag when to adjust — so you avoid surprises at regularization. It also keeps all documents in one place and syncs invoices with your taxes.
Bottom line
To register as autónomo with Social Security in 2026, use Importass, file on or before your start date, and have these ready: IAE and CNAE codes, your start date, a net income estimate, your mutua choice, and your IBAN. Pick a contribution base that reflects your income, use the €88 flat rate if you qualify, and monitor your charges each month.
