The Spanish Social Security number (número de la Seguridad Social, often shortened to NUSS) is the number that identifies you to Social Security for your whole life. You need it to work in Spain, as an employee or as a self-employed autónomo, to pay contributions and to claim any benefit. You apply once. It does not change when you change job, scheme or city. This post is part of our guide to foreigners in Spain: NIE, Social Security and tax.
Here is what the law says it is, who applies for it in each case, how to request it on Import@ss or at an office and how to find yours if you already have one.
What the Social Security number is
The Tesorería General de la Seguridad Social (the Social Security treasury, TGSS) assigns a Social Security number to each person to identify them in their dealings with Social Security, as a member registered in any of its schemes, whether employed or self-employed (article 21.1 of Real Decreto 84/1996, which approves the general regulation on company registration and affiliation). It is also assigned to people receiving pensions or other benefits, contributory or not.
Social Security explains in its official magazine that the NUSS is the same as the affiliation number (NAF, número de afiliación): the Social Security number becomes your affiliation number when you first start an activity that brings you into the system.
This number is not your NIE or your DNI. The NIE identifies you to every public body and is your tax number; the NUSS only identifies you to Social Security. We explain the NIE in what the NIE is.
Affiliation and registration: once for life and once per job
These are two separate acts that are easy to mix up.
- Affiliation (afiliación) is the act by which the Tesorería recognises that you are in the system, the first time you do an activity that requires it. It is compulsory, single for all schemes, lasts your whole life and is exclusive (article 6 of Real Decreto 84/1996 and article 15 of the Ley General de la Seguridad Social).
- Registration (alta) is the act that places you in the scheme matching each activity you start. There is a registration and a deregistration (baja) for each job (article 7 of Real Decreto 84/1996).
So if you stop working for a few years and come back, you are not affiliated again: you are registered with the same number.
Who needs it
The Social Security system covers Spaniards living in Spain and foreign nationals who live or are legally present in Spain, provided they work in Spain as employees, self-employed workers or the other groups the law lists (article 7.1 of the Ley General de la Seguridad Social). All of them need the number before their first registration.
According to Social Security, your region's health service also uses your affiliation number to issue your health card (tarjeta sanitaria). The card is not the number: it is issued from it.
Who applies in each case
The regulation distinguishes according to how you will work (articles 23 to 25 of Real Decreto 84/1996):
- If a company hires you and you are not yet affiliated, the company must apply for your affiliation (article 24). Social Security states that if you have no number, the company also makes that request. You give it your details before you start work (article 21.3).
- If you will be self-employed and are not affiliated, the application is yours (article 25.1).
- If your employer does not do it, you can apply for your affiliation and registration directly at the Tesorería (article 25.2).
- The Tesorería can also affiliate you on its own initiative (article 23).
How to apply
The general rule is in article 21.2 of Real Decreto 84/1996: anyone without a number must request it from the Tesorería General before applying for affiliation and registration, showing their DNI or, for a foreign national, their identity document. Today there are two ways to do it.
Online, on Import@ss
Import@ss is the Tesorería's online portal. According to Social Security, the service is called "Solicitar el Número de la Seguridad Social" (request your Social Security number). You can identify yourself with:
- Cl@ve permanente or Cl@ve Móvil (the government's online login system);
- a code sent by SMS;
- an electronic DNI or a digital certificate.
If you have none of these, you can still apply on Import@ss with your identity document (DNI, NIE or passport), an email address, a device with a camera to take a photo of yourself and the application form for a Social Security number and change of details, form TA.1. Once the number is assigned, a decision is issued that you can print.
At a Tesorería office
You can also apply at a provincial office (Dirección Provincial or Administración) of the Tesorería General de la Seguridad Social with your identity document (article 21.2), usually on form TA.1.
If you already have one and do not know it
Many people already have a number without knowing it, from a previous job in Spain or from studying here. Before applying for a new one, check:
- on Import@ss, in your personal area or in the service "Acreditación del Número de la Seguridad Social", which lets you download a PDF proving it;
- on a previous payslip or employment contract;
- on your employment history report (informe de vida laboral).
After the number: registering as self-employed
If you will work for yourself, once you have the number the next step is registering with the self-employed scheme, which we explain in form TA.0521. The monthly contribution is covered in Social Security contributions for autónomos. The full route, including registering with the tax agency, is in how to become an autónomo in Spain. What changes for a foreign national is in foreign autónomos in Spain.
Remember that your Social Security number does not decide where you pay tax. You can pay contributions in Spain and not be tax resident in a given year, or the other way round: see tax residency versus legal residence.
