Here's exactly how to register as autónomo with Social Security using Importass. You'll see the steps, the data you need, the deadlines, how to choose your contribution base and how the 88 € flat rate works. Since 2018 the process is 100% online, so you'll need Cl@ve or a digital certificate.
Do I register with the AEAT or with Social Security first?
You can do both on the same day. In practice, do the AEAT registration first so you already have your IAE code. The dates on both registrations must match.
Can I file my registration in advance?
Yes. You can file your alta up to 60 days before your start date.
Which login method do I need?
Cl@ve or a digital certificate. Both work in Importass.
What if I start working before filing my alta?
You can still register, but it will be filed out of deadline. It can trigger surcharges or back payments.
When is the payment charged?
The last working day of each month, by direct debit.
Is the 88 € flat rate for everyone?
It applies to new autónomos who meet the requirements. If your income stays below the minimum wage, you can extend it for another 12 months.
Want to understand the full regime first? Read the full autónomo guide.
Prerequisite: have your AEAT registration done with your IAE code.
1. Go to Importass
Select "Altas, bajas y modificaciones" and then "Alta en trabajo autónomo".
2. Identify yourself
Use your Cl@ve credentials or your digital certificate.
3. Have this ready
4. Complete the form sections
Before you start. You must be registered in RETA on the same day or before your first day of activity.
The 60-day window. You can file your alta up to 60 days early to avoid last-minute issues.
Late alta. Allowed, but it can trigger surcharges.
Coordinate with the AEAT. Most people file both registrations on the same day.
The current system uses brackets based on real income. You estimate your average monthly net income and pick a base in the matching bracket. Your monthly quota depends on that base.
Simple rule: pick a base in line with your income and adjust during the year if your situation changes. For all the brackets and quotas, see the autónomo contributions guide.
The mutua manages your benefits. You have to pick one during the alta.
Pick a mutua with strong digital management. You can switch later if you need to.
Autónomo societario.
If you own or manage a company and meet certain requirements, you register as autónomo societario. The Importass process is the same, but you also include your company's details.
Multiple activities.
You only have one RETA registration, but the activity data should reflect everything you do. You can update it later in Importass.
Foreign nationals.
Non-EU citizens need a valid work authorization before the alta. With that permit, the Importass process is identical.
Use Importass, file the alta the same day or before you start, and have ready: IAE and CNAE, start date, income estimate, mutua and bank account. Pick a base that matches your income, apply the 88 € flat rate if you qualify and review your charges every month.
To understand the full autónomo registration process, see our complete guide: how to register as autónomo.
