Invoicing foreign clients as a solo entrepreneur in Portugal: it's simpler than you think.

When I moved to Portugal and registered as a freelancer, the first thing I had to learn was how invoicing works here. It's different from Sweden, different from most of the EU, and nobody explains it well. I spent years using a workaround that turned out to be unnecessary. Here's what I wish someone had told me.

The simplified regime: how solo entrepreneurs work in Portugal

If you're a solo entrepreneur in Portugal (trabalhador independente), you're most likely on the regime simplificado (simplified regime). It's the default tax setup for freelancers and sole traders under a certain revenue threshold, and almost everyone starts here.

The single most important thing about the simplified regime: your income tax (IRS) and Social Security contributions are based on when you receive payment, not when you issue an invoice. This is cash-basis accounting, and it applies regardless of which document type you use.

Let me say that again, because this is where the confusion lives: whether you issue an invoice-receipt (Recibo Verde, FR series) or a standard invoice (fatura, FT series) followed by a separate receipt, your tax obligation is triggered by payment. The document type doesn't change when you owe tax. Both workflows preserve cash-basis accounting for solo entrepreneurs on the simplified regime.

Two ways to invoice, same tax timing

Portugal gives solo entrepreneurs two invoicing workflows:

Invoice-receipt (fatura-recibo, FR): the Recibo Verde. One document issued at the time of payment that serves as both invoice and receipt. This is what most solo entrepreneurs use for domestic clients. Simple, one step, done.

Invoice + receipt (fatura FT + recibo RC): a two-step process. You issue a standard invoice (fatura) when the work is done or when the client needs a document for their accounts payable. Later, when payment arrives, you issue a separate receipt (recibo) to confirm payment. Both documents are issued through certified software or the AT portal.

In both cases, your IRS income is recognized when payment is received. Your Social Security contributions are calculated on payments received. The tax timing is identical.

Why the two-step process exists

The two-step process exists precisely for situations where your client needs an invoice before they can pay you, which is how most B2B works internationally.

When I finish a project for a client in Stockholm, their accounts payable team needs a document they can book as a payable. An invoice with a due date, my bank details, a line item breakdown. They enter it into their system, it gets approved, and payment goes out on the due date.

With the two-step process, I issue a fatura (FT series) through certified invoicing software. My client gets a proper, legally valid invoice they can process. When they pay, I issue a receipt (RC series) to close the transaction. My income is recognized at payment, not at invoice issuance.

This is exactly how invoicing works in most of Europe. The only difference is that Portugal also offers the simpler one-step Recibo Verde for situations where invoicing and payment happen at the same time.

The myth I believed for years

Here's the part where I was wrong, and where I've heard many other freelancers repeat the same mistake.

I believed that issuing a standard fatura (FT) through certified software would switch me to accrual-basis accounting, that I'd owe tax on the invoice amount the moment I issued it, regardless of whether the client had paid. So I avoided it. Instead, I sent clients an informal "commercial invoice" (a PDF I made myself, not through any certified system) and only issued the Recibo Verde when payment arrived.

My accountant told me to do this. Other freelancers told me the same thing. It became "what everyone does."

But it's wrong. Or rather, it's an unnecessary workaround for a problem that doesn't exist.

The simplified regime's cash-basis treatment applies to your income tax and Social Security regardless of which certified document type you use. The distinction between cash-basis and accrual-basis in Portugal is about your tax regime, not your document type. Solo entrepreneurs on the simplified regime are on cash-basis. Period.

The only thing issuing a fatura does is create a VAT obligation at the point of issuance (if you're not VAT-exempt). But for IRS and Social Security (which are typically the larger concern) the timing follows payment.

What you should actually do

If you're a solo entrepreneur in Portugal invoicing foreign clients:

1. Use certified invoicing software to issue a proper fatura (FT series) when you need to send your client an invoice before payment.
2. When payment arrives, issue a receipt (RC series) through the same certified software.
3. Your income is recognized at payment, not at invoice issuance. Your IRS return and Social Security contributions reflect when money actually arrived.

For domestic clients where invoicing and payment happen together, continue using Recibos Verdes (FR series) through the Portal das Finanças. It's simpler and achieves the same thing in one step.

The only administrative overhead of the two-step process is that you need to remember to issue the receipt when payment arrives. That's it. That's the entire trade-off.

Why the myth persists

I think the confusion comes from a few places:

Mixing up VAT timing with income tax timing. If you're on the normal VAT regime (not Art. 53 exempt), issuing a fatura does create a VAT obligation at issuance. People conflate this with "creates a tax obligation" and assume it means income tax too. It doesn't. VAT and IRS have different timing rules.

The Recibo Verde's elegance. The Recibo Verde is genuinely clever, one document, one step, everything handled. It's natural to assume it must be doing something special that a regular fatura doesn't. But the cash-basis treatment comes from the simplified regime itself, not from the document type.

Accountants recommending the path of least resistance. The "commercial invoice + Recibo Verde" workaround works. It doesn't cause problems. So accountants keep recommending it. But "works" and "necessary" are different things.

The bottom line

You don't need a workaround to invoice foreign clients while keeping cash-basis accounting. The simplified regime gives you cash-basis regardless. Use the two-step process (fatura + receipt) through certified software, and your tax timing is exactly the same as with Recibos Verdes.

The system works. It just took me a few years to realize it.

Related: VAT in Portugal as a solo entrepreneur, the full breakdown of when you charge VAT, when you don't, and which exemption code to use.

Related: Why every freelancer in Portugal talks about "green receipts", the history of the Recibo Verde, from 1978 paper booklets to the Portal das Finanças.

Related: Best invoicing software for Portuguese freelancers in 2026, how to pick AT-certified software that handles both domestic and foreign-client workflows.