Tax Authority (Finanças)Automatic collection

Proof of Start of Activity (Comprovativo de Início de Atividade)

Proof of the declaration registering the start of an activity with the Tax Authority (Finanças), showing the start date, activity codes and tax regime.

What it is for

Confirm the start date of the activity and the CAE or CIRS codes declared.
Provide proof of tax registration to an organisation that requests it.
Review the details with your accountant.

Example (fictitious). Rita starts giving private lessons as a self-employed worker. The school where she will work asks for proof that she is registered with the Tax Authority, and she provides this proof.

What it is

This is the proof of the declaration submitted to the AT to register the start of a professional or business activity. It shows the declared details, the start date and the tax regime. For the simplified declaration, it includes a code that allows its authenticity to be verified.

How we collect it

We request it using the holder's NIF and Tax Portal (Portal das Finanças) password and deliver the official PDF of the proof.

Access required: Tax Portal (Portal das Finanças). Credentials are encrypted only during the collection and deleted at the end.

Things to note

It confirms a tax declaration; it does not grant a professional licence or prove income. There may have been changes or a cessation afterwards, so check the sequence of declarations before concluding that the activity is still open.

Frequently asked questions

Does registering an activity with the Tax Authority allow me to practise any profession?

No. Tax registration does not replace the licences or qualifications specific to each profession, which are dealt with by the competent authority.

Does this document show how much I earn?

No, only the details declared at registration. For income, you need receipts, your IRS return or other documents for the period.