The digital mobile key

Image: Teleporto.

The Chave Móvel Digital is the state’s login. It ties a mobile number to a passport, a citizen card, or a residence card. With it you can sign in to the tax office, Social Security and the SNS 24 health portal, and you can sign some documents, without a new password for every site.

You need a Portuguese mobile number first. A foreign SIM usually cannot receive the code. The prepaid options are in the phone-number guide.

What you actually type

The key has two parts: a four-digit PIN you choose, and a six-digit code that arrives by SMS, email or a phone notification and dies after a few minutes. The official walkthrough is on justiça.gov.pt. Activation itself is explained at autenticacao.gov.pt.

For a foreigner the key is linked to the passport or the residence document, not to a NIF. You still want the NIF. Banks, landlords and contracts ask for it separately. That step is in Getting a NIF in Porto.

Where it pays off

• Portal das Finanças, for the tax number and later the tax return.
• Segurança Social Direta, once you have a NISS.
• The SNS 24 personal area, for appointments and prescriptions.

This is not a legal guide. The justice site is the list of where to request the key, and that list can change.

Checked 24 October 2026. If an official page disagrees, follow that page.