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How to register as a self-employed worker with the Portuguese Tax Authority (Autoridade Tributária e Aduaneira, AT)?

How to register as a self-employed worker with the Portuguese Tax Authority (Autoridade Tributária e Aduaneira, AT)?

Portuguese Tax Portal: How to log In and register your activity?

Updated over 2 months ago

If you plan to start working as a Self-Employed Worker (Trabalhador Independente, TI) or Sole Proprietor (Empresário em Nome Individual, ENI), it’s essential to understand the applicable tax rules, as they differ from those for employees with a work contract. The first step is registering your activity with the Portuguese Tax Authority (Autoridade Tributária e Aduaneira, AT). In this article, we’ll guide you through the process step by step.

What is the difference between TI and ENI?

The main difference between TI (Self-Employed Worker) and ENI (Sole Proprietor) lies in the level of formality and the type of activity:

  • TI (Self-Employed Worker) – Works independently, providing services or working on a contract basis, similar to a freelancer. This status is typically chosen for smaller-scale and less formalized activities.

  • ENI (Sole Proprietor) – Operates a more structured business, such as retail, larger-scale services, or activities requiring employees or rental space. While still legally considered an individual, an ENI operates more like a full-fledged business.

Comparison between TI and ENI

Criteria

TI (Self-Employed Worker)

ENI (Sole Proprietor)

Accounting

Simplified (usually under a simplified tax regime)

Can opt for organized accounting

Activity Type

Professional services

Commercial activity and retail sales

Legal Status

No separate legal entity (individual person)

No, considered an individual person but with business-like characteristics

VAT (IVA)

Can be exempt if income is below the threshold

Can also be exempt, but usually subject to VAT

Purpose

Freelance or contract work

Business operations requiring a formal structure

Who Needs to Register a Business Activity with the Tax Authorities?

All Self-Employed Workers (TI) and Sole Proprietors (ENI) are required to register their activity with the tax authorities. Whether you work as a full-time freelancer or have a regular job and just want to earn extra income, you must notify the Tax and Customs Authority (AT) for income tax (IRS) and VAT (IVA) purposes.

Who Can Register?

The following individuals can open a business activity with the tax authorities:

  • All residents in Portugal

  • Non-residents, as long as they are required to file a tax return in Portugal.

Open Activity with the Tax Authorities: Step by Step

Before starting your activity as a Self-Employed Worker (TI) or Sole Proprietor (ENI), you must express this intention to the Tax Authorities, so you need to start by opening an activity. This can be done in two options.

Option 1 - At a tax office

To open an activity in person, simply go to the tax office in your area of residence with the following documents:

  • Citizen Card or Residence Permit

  • Bank Identification Number (NIB)

When it’s your turn, inform the staff that you want to open an activity and indicate which accounting regime you prefer to choose (below, a useful link: Tips on starting an activity). Important: This request must be made before starting self-employed work or at least before issuing invoices.

Option 2 - Online through the Finance Portal

The first step to opening an activity online is to access the Finance Portal through the website and log in. In the upper right corner, you will find the option "Iniciar Sessão" (Log In). When you click it, you will be asked to enter your taxpayer number (NIF) and password. If this is your first time accessing the portal, you should select "Registar-se" (Register). After completing the registration, a password will be sent to you by mail.

What Happens After Registration?

After logging in, go to "Todos os Serviços" (All Services), select "Início de Atividade" (Start Activity), then "Entregar Declaração" (Submit Declaration).

You can also access it directly: Finance Portal - Start Activity.

On the new page, click "Submeter Declarações" (Submit Declarations).

Additional Resources

📌 Need a visual guide? Watch a detailed step-by-step video by Prof. Danielle Lago on YouTube: How to Register an Activity in Portugal.

By following these steps, you can legally start your self-employed activity in Portugal and ensure compliance with tax obligations. 🚀

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