If you are going to work for yourself regularly in Portugal, you normally need to open activity with Finanças before you start. This is the tax registration step that tells the Autoridade Tributária what you do, when you start, how much turnover you expect and how you should initially be treated for IRS and IVA. It is not the same thing as merely having a NIF, and it is not the same thing as creating a company.

Fast answer: a freelancer or other individual carrying on habitual independent activity should normally submit a declaração de início de atividade before starting — at the latest on the start date entered in the declaration. You can do it online through Portal das Finanças or in person at a Serviço de Finanças / participating Loja do Cidadão.

Who needs to open activity?

Finanças says that people who independently and habitually carry on production, commerce or services — including agricultural and extractive activities — must submit a declaration of commencement of activity. If you will do more than a genuinely isolated one-off transaction, do not assume an ato isolado can replace opening activity.

gov.pt — Open activity with Finanças · Autoridade Tributária — Início de atividade

When must you do it?

For an individual starting Category B business/professional activity, the declaration is generally due before the activity starts. The gov.pt service describes this as before starting, at the latest on the day you state as the activity start date.

There is a different registration timetable for entities that have first been created through a commercial register. A person/entity subject to commercial registration generally has an additional deadline of 15 days after the registration filing, but still has to deal with the tax commencement declaration before the activity actually begins. Companies and organised-accounting cases normally involve a contabilista certificado.

Finanças — start/change/cessation FAQs

How to open activity online

  1. Go to Portal das Finanças and sign in with your NIF/password or supported digital authentication.
  2. Open the ATividade area and choose the option to submit a declaration of activity / início de atividade.
  3. Answer the guided questionnaire if you are an individual without organised accounting. Finanças uses your answers to infer parts of the initial IRS/IVA treatment.
  4. Review every field and the automatically calculated tax framing before submitting.
  5. Save/download the submitted declaration and confirmation. You may need it for banks, clients, insurers or other administration.
In person: you can also use a Serviço de Finanças, and some Lojas do Cidadão have a Finanças desk. If you are unsure how a complicated activity should be classified, an accountant can be cheaper than fixing the wrong setup later.

Information you should decide before you start

The declaration is not merely your name and NIF. Be ready to answer questions about:

  • Start date — use the real date the activity begins.
  • Activity code — CAE and/or the applicable CIRS professional activity code. Use SICAE and Finanças guidance rather than copying another person’s code.
  • Main and secondary activities if you do more than one type of work.
  • Expected annual turnover — this can affect the initial IVA framing and other obligations.
  • IRS accounting regime — simplified regime or organised accounting where applicable.
  • IVA position — Article 53 exemption, Article 9 exemption or normal VAT treatment depending on the activity and circumstances.
  • Where the activity is carried on and relevant establishment/address information.
  • Foreign/EU transactions if you expect to supply or purchase cross-border services/goods.
  • Bank/IBAN and contact details where requested/appropriate.

CAE versus CIRS code

CAE codes classify economic activities. Some independent professionals also use the professional-activity list associated with Article 151 of the IRS Code. The correct choice matters because it can affect invoicing, tax coefficients, licences and statistical/administrative classification. Do not choose a broad code merely because it sounds approximately right.

SICAE — official CAE search

What happens with Social Security?

When an individual opens independent activity with Finanças, the information is communicated to Segurança Social. That does not mean every independent worker immediately starts paying the same contribution on day one. First-time independent activity has its own commencement rules, and mixed salaried/self-employed work can create different contribution outcomes. See our dedicated Social Security guide rather than treating the Finanças declaration as the whole process.

What happens with IVA and IRS?

Finanças uses the information in the declaration to establish your initial tax framing. This is why your expected turnover and activity description matter. Opening activity does not mean that you necessarily charge 23% IVA, nor does an IVA exemption mean the income is exempt from IRS. IVA and income tax are separate systems.

For the current thresholds, rates and simplified-regime coefficients, see our supplementary guide Business taxes in Portugal: IVA, IRS and IRC explained.

Foreign clients and working across borders

If you live in Portugal but invoice customers abroad, do not select your IVA treatment solely from the customer’s country or from a template invoice. Business-to-business EU services, services to consumers, exports and services supplied outside Portugal can have different place-of-supply and reporting rules. Tell Finanças/accountant what you actually expect to do when you open activity.

If you already have an employment contract

You can have salaried employment and also open independent activity. That does not remove the need to register the independent activity. It can, however, affect Social Security contributions and your overall IRS position. Keep the two income streams distinct in your records.

Changes after opening activity

If information in the original declaration changes — for example your activity, expected turnover, address or other relevant registration data — you may need a declaração de alterações. The general IRS rule is to report changes within 15 days unless another specific deadline applies.

CIRS Article 112 — start, changes and cessation

Stopping the activity

Do not simply stop issuing invoices and leave the activity open indefinitely. When the activity genuinely ends, submit a cessation declaration. The current general rule is within 30 days of cessation. An open activity can continue to create filing and administrative obligations even if you have stopped earning income.

Common mistakes

  • Thinking a NIF means your freelance activity is already registered.
  • Opening activity after you have already been working/invoicing regularly.
  • Choosing the wrong CAE/CIRS code because someone else uses it.
  • Entering an unrealistic turnover estimate without understanding the IVA consequences.
  • Assuming Article 53 means the income is “tax free”.
  • Ignoring foreign clients when answering the activity questionnaire.
  • Forgetting to file an alteration when the business changes.
  • Stopping work but never closing the activity.

Quick checklist

  1. Have your NIF and Portal das Finanças access ready.
  2. Identify the correct CAE/CIRS activity code.
  3. Choose a realistic start date and expected turnover.
  4. Understand simplified vs organised accounting.
  5. Check the likely IVA regime and cross-border activity.
  6. Submit before starting regular independent work.
  7. Save the declaration/confirmation.
  8. Check Segurança Social after opening.
  9. Issue the correct invoice/receipt from the first transaction.
  10. Report later changes and close the activity when it genuinely ends.

Official links

Last verified: 2 October 2026. Tax registration and IVA rules can change. Cross-border activities and organised accounting can be materially more complex than the standard online questionnaire.