NIE & Social Security in Spain — essential steps for international students and interns.

Every foreigner in Spain — regardless of whether they are an EU citizen, student, worker, or property owner — needs a NIE for almost any interaction with the Spanish state or financial system. The NIE itself is a letter followed by seven digits and a check letter (e.g. X-1234567-Z). It does not expire as a number, but if it is linked to a temporary residence permit (as it is for non-EU citizens holding a TIE), the permit must be renewed when the visa period ends. EU citizens receive a standalone NIE certificate; non-EU citizens receive a TIE biometric card that carries the NIE.

The Social Security number (Número de Afiliación) is Spain's system for tracking contributions to the public social insurance fund. Every person who works or earns income in Spain — whether employed, self-employed, or interning in a paid placement — must be registered. In practice, for paid internships, the host company submits Form TA.1 to the Tesorería General de la Seguridad Social before the intern starts work. The number is permanent and does not need to be renewed. However, you cannot apply for it without first having your NIE, making the NIE the first step in this chain of documentation.

In theory the cita previa system is simple: go to the sede electrónica of the Policía Nacional, pick your province, pick 'Asignación de NIE' or 'Policía — Toma de huellas (Expedición de tarjeta)' for TIE, choose a slot. In practice, in Madrid, Barcelona, Valencia, Málaga, and Alicante — the five provinces where 80% of our students end up — the appointment portal is fully booked out weeks in advance and new slots trickle in unpredictably as cancellations release. The trick is knowing when to look, which office to book, and how to avoid the third-party 'cita mafia' resellers that charge €30–€80 for a slot that is legally free.

New slots release most reliably around 8:00 and 20:00 on weekdays, plus a smaller batch on Sunday evenings. If your city's Policía Nacional office is fully booked, look at satellite offices in the same province — for example, Getafe or Alcalá de Henares for Madrid province, Sabadell or Terrassa for Barcelona province. A slot 40 km away is usually faster than waiting a month for the city-centre office. Never pay a reseller: many of the slots they sell are auto-cancelled by the system when it detects bot booking, leaving you both out of pocket and without an appointment.

Every NIE, TIE, and Social Security procedure has a specific form code and, where applicable, a specific Modelo 790 tax code. Filing the wrong form or paying the wrong 790 code is a common reason for being turned away at the counter — the officer will not process the file even if all your other documents are correct. Fees are updated annually by the Ministry of Interior; the amounts below reflect the 2026 tariff.

The Social Security number (Número de Afiliación, also written NUSS) is Spain's system for tracking contributions to the public social insurance fund. Every person who works or earns income in Spain — whether employed, self-employed, or interning in a paid placement — must be registered. Since Royal Decree-Law 2/2023, even unpaid interns whose placement is covered by a Training Agreement (convenio de cooperación educativa) must be affiliated to Social Security under a reduced-contribution regime, though the contribution is paid by the host company or educational institution, not by the intern.

For paid internships, the host company submits Form TA.1 to the Tesorería General de la Seguridad Social to request the NUSS if you don't already have one, then Form TA.2/S to declare the alta (start of activity) before your first working day. The number is permanent and does not need to be renewed. However, you cannot apply for it without first having your NIE, making the NIE the first step in this chain of documentation. Failure to register an intern before day one exposes the host company to fines starting at €7,500 per unregistered intern, so this is a step companies take seriously.

The NIE unlocks the rest of your setup in Spain, and the smart move is to sequence the next steps in the right order so each one supports the next. The padrón (municipal registration) is often the second document you'll need, because most Spanish banks now require it to open a full resident account. Some challenger banks (N26, Revolut, BBVA's Blue account) will open with just a passport and NIE, but you'll hit friction later — for example, when you want to receive a paid internship stipend via SEPA transfer or to sign a rental contract in your own name.

Phone contracts and utilities are the third layer. Prepaid SIMs are available at any tobacconist with just your passport, but a monthly contract with data — which is normally cheaper than prepaid over three months — requires NIE and a Spanish IBAN. Landlords, gyms, coworking spaces, and even public library cards will ask for the NIE + padrón combination. Getting these three documents (NIE, padrón, Spanish bank account) sorted in your first two weeks removes 90% of the administrative friction of your stay.