Understanding the Autoridade Tributária e Aduaneira (AT): Portugal’s Tax and Customs Authority

If you live, work, or own property in Portugal, you’ll soon come across the Autoridade Tributária e Aduaneira (AT) — often referred to simply as the Tax and Customs Authority. This government body is responsible for collecting taxes, managing customs duties, and ensuring compliance with Portuguese tax law. Whether you’re an expatriate settling in the Algarve, a remote worker in Lisbon, or a property investor on the Silver Coast, understanding how the AT works can make life in Portugal much smoother.

What is the Autoridade Tributária e Aduaneira?

The Autoridade Tributária e Aduaneira (AT) operates under the Portuguese Ministry of Finance and oversees all matters related to taxation and customs. Its main role is to ensure that individuals and businesses fulfil their fiscal obligations, from income tax to VAT and property taxes, while also facilitating trade and customs control across Portugal’s borders.

You might hear people simply refer to it as “Finanças”, which is the name of the local tax office (Serviço de Finanças) where you’ll deal directly with the AT.

Autoridade Tributária e Aduaneira

Key responsibilities of the AT

The AT has a wide range of functions, but for residents, expats, and property owners, the most relevant include:

• Tax collection and management: Handling all types of taxes such as IRS (personal income tax), IRC (corporate tax), IVA (VAT), and IMI (municipal property tax).
• Customs control: Overseeing imports, exports, and customs duties within and outside the EU.
• Combatting tax evasion and fraud: Ensuring compliance with national and EU regulations.
• Issuing the NIF (Número de Identificação Fiscal): A vital tax identification number required for almost every financial or legal transaction in Portugal.

The NIF: your first step with the AT

If you plan to live, work, or purchase property in Portugal, obtaining a NIF number is one of the first and most important steps.
The NIF is your unique tax identification number, issued by the AT, and it’s essential for things like:

• Opening a bank account
• Signing a rental or employment contract
• Buying property
• Registering for utilities
• Submitting tax returns

You can request a NIF at your local Finanças office or online through a legal representative if you’re not yet a resident.

Accessing the AT online: Portal das Finanças

The Portal das Finanças is the AT’s official online platform, allowing taxpayers to manage their obligations digitally.
Through this portal, you can:

• File your annual IRS tax return
• Check tax payments and deadlines
• Pay IMI or IUC (vehicle tax) online
• Request official documents and certificates
• Update your tax information

The website is primarily in Portuguese, but with a bit of patience — or help from a local accountant — it’s a valuable tool for managing your taxes efficiently.

Property owners and the AT

If you own property in Portugal, you’ll have ongoing contact with the AT, mainly through IMI (Imposto Municipal sobre Imóveis). This annual municipal property tax is based on the property’s taxable value (VPT) and is paid to your local Finanças office.
Other taxes that may apply include:

• AIMI (Additional Property Tax): Applicable to high-value properties.
• IMT (Property Transfer Tax): Paid when purchasing real estate.
• Stamp Duty (Imposto do Selo): Charged on certain transactions and contracts.

Staying informed about deadlines and rates is essential to avoid fines or penalties.

Support for expats and foreign residents

Many foreigners living in Portugal find the tax system complex at first, especially if they’re used to different procedures back home. However, the AT provides helpful resources and collaborates with tax professionals who can assist in English. For expats, the key is to:

• Keep your NIF and Finanças login secure.
• Stay up to date on tax deadlines (especially the annual IRS submission).
• Consider hiring a certified contabilista (accountant) familiar with international taxation and residency matters.

Understanding how the Autoridade Tributária e Aduaneira works is essential for anyone planning to live, work, or invest in Portugal. From issuing your NIF to managing property taxes and customs, the AT plays a central role in the country’s fiscal system. While the procedures may seem complex at first, using the Portal das Finanças and seeking professional advice when needed can make navigating Portugal’s tax landscape much easier.