How do I register as self-employed (início de atividade) in Portugal?

Checked on 2026-10-25

Before you start any self-employed activity in Portugal, the law requires you to file a start-of-activity declaration (declaração de início de atividade) with the tax office; it can also be sent electronically. Changes must be declared within 15 days and closing the activity within 30 days. The tax authority then informs Social Security.

Key facts

What	The law says	Source
When to register	Before starting any activity that can produce business or professional (category B) income	Código do IRS, art. 112(1)
Where	At a tax office (serviço de finanças), on the official form, or electronically	Código do IRS, art. 112(1), (7)
Changes (address, activity, etc.)	Declare within 15 days of the change	Código do IRS, art. 112(2)
Closing the activity	Declare within 30 days of the cessation date	Código do IRS, art. 112(3)
Invoices and receipts	Issue an invoice, receipt or invoice-receipt in the tax authority’s apps for every amount received, or invoices under the VAT Code plus a receipt	Código do IRS, art. 115(1)
First-year tax regime	Set by the estimated annual income you give in the declaration	Código do IRS, art. 28(10)
Social Security	The tax authority informs Social Security, which registers you	ISS Guia Prático, B “Identificação”

The declaration

Income from commercial or industrial activity and from providing services on your own account is business and professional (category B) income under the IRS Code (art. 3(1)). Article 112 says the start-of-activity declaration must be filed before you start. Where the tax office has the IT means, it can be made verbally, typed into the system and confirmed by you on a printed standard document, which then replaces the written declaration (art. 112(4)–(5)). The law also allows the declaration to be sent electronically (art. 112(7)).

In the declaration you give an estimate of your annual income. Article 28(10) says that, in the first year, this estimate decides whether you are taxed under the simplified regime, unless you choose organised accounting there (art. 28(4)(a)).

After you register

Invoicing. Article 115 requires you to issue an invoice, receipt or invoice-receipt for every amount clients pay you, including advances and expense reimbursements, using the tax authority’s invoicing apps, or to issue VAT-Code invoices and a receipt for each payment.
Social Security. The Social Security Institute’s guide says the tax authority passes your start of activity to Social Security, which registers you and notifies you. You don’t file a separate registration.
Changes and closing. Any change to the declared data within 15 days; closing within 30 days (art. 112(2)–(3)).

Who must keep the simplified regime: anyone whose gross category B income did not exceed €200,000 in the previous year (Código do IRS, art. 28(2)).
When Social Security contributions start: for a first registration, on the first day of the 12th month after the start of activity (ISS Guia Prático, B).

Sources

Código do IRS, art. 112.º – Declaração de início de atividade, de alterações e de cessação (Portal das Finanças, AT) checked 2026-10-25
Código do IRS, art. 115.º – Emissão de recibos e faturas (Portal das Finanças, AT) checked 2026-10-25
Código do IRS, art. 28.º – Formas de determinação dos rendimentos empresariais e profissionais (Portal das Finanças, AT) checked 2026-10-25
Código do IRS, art. 3.º – Rendimentos da categoria B (Portal das Finanças, AT) checked 2026-10-25
Instituto da Segurança Social, Guia Prático – Novo Regime dos Trabalhadores Independentes (1009 – v1.14, published 16 May 2025) checked 2026-10-25

Change history

2026-10-25: Page created

This is general information, not legal advice, and Lumen is not a law firm. Rules change and offices differ: check the official sources above before you act. Found something wrong or out of date? Write to support@lumen.observer.