Double Taxation: How to Avoid Paying Tax Twice on Income

Double taxation happens when two countries tax the same income, for example when a foreign client withholds tax and Spain also taxes you as a resident. For most freelancers it is rare, but when it appears it can cost real money unless you know the mechanisms that prevent it.

The short answer: Spain taxes its residents on worldwide income, and tax treaties plus Spanish domestic rules reduce or remove double taxation. The usual solution is to declare the income in Spain and claim a deduction for the foreign tax paid, limited to the Spanish tax that corresponds to that income. You need proof of the foreign tax, and the treaty with the other country decides which side may tax what.

Double taxation relief is technical and depends on the treaty, the type of income and the facts. This guide is general information, not tax advice. Consult a tax adviser before you rely on a treaty position.

Key takeaways: double taxation

Double taxation means the same income is taxed in two countries.
As a Spanish tax resident, you declare worldwide income and can claim relief for tax paid abroad.
The deduction is limited to the Spanish tax on that income, so you may still pay a net amount.
Treaties decide which country has the right to tax each type of income and cap foreign rates.
Keep a certificate or proof of the foreign tax paid.

In this guide

How double taxation arises for freelancers

Most freelancers who work from Spain for foreign clients pay tax only in Spain, because services performed in Spain are generally taxed where the work is done. Double taxation appears when another country also claims a right to tax, for instance:

A client withholds tax at source on royalties, licences or certain service fees.
You perform work physically in another country and it taxes the income.
You earn income from a foreign property or investment.
A platform or payer applies a default withholding because it lacks your tax documents.

For the withholding side, see withholding on foreign payments for freelancers.

Two ways to relieve double taxation

Mechanism	How it works
Tax treaty	Spain has agreements with many countries that allocate taxing rights and limit the rates at source. They may reduce the foreign tax before it is collected.
Foreign tax credit (deduction in Spain)	If foreign tax was paid, you deduct it from your Spanish tax, up to the Spanish tax corresponding to the foreign income

The treaty network is covered in Spain tax treaties by country.

How the foreign tax credit works

You declare the full income in Spain, converted to euros, and then claim a deduction for the tax actually paid abroad. The deduction cannot exceed the lower of two amounts: the foreign tax paid and the Spanish tax that corresponds to that income. If the foreign tax is higher than the Spanish tax, the excess is not refunded by Spain; you may try to recover it from the foreign country or carry it forward where the rules allow it.

Example of double taxation relief

A freelancer receives EUR 10,000 from a foreign payer that withholds 15% (EUR 1,500). The figures are illustrative only.

Item	Amount
Gross income	€10,000
Foreign tax withheld	€1,500
Cash received	€8,500
Spanish tax on this income at, say, 30%	€3,000
Deduction for foreign tax	€1,500 (lower than €3,000)
Additional Spanish tax to pay	€1,500

In total you pay €3,000, the same as if the income had been taxed only in Spain, with €1,500 collected by the foreign country and €1,500 by Spain. If the foreign rate had been 35%, the deduction would be capped at €3,000 and the extra €500 would be a real cost.

What you need to claim relief

A certificate or statement from the payer showing the gross income and the tax withheld.
Proof that the tax was paid to the foreign authority, when requested.
Your invoice, contract and payment record.
The exchange rate used to convert the income and the tax into euros.
A certificate of Spanish tax residence for the foreign payer, to apply the treaty rate at source.

How to reduce the risk of double taxation

Check before you sign whether the client’s country withholds on payments to foreign freelancers.
Give the payer your tax residence certificate and the forms it asks for. For US clients, see the W-8BEN form guide.
Avoid working physically in the client’s country without checking the tax effect.
Agree in the contract that payments are made gross, or that the client grosses up any tax withheld.
Ask your gestor to review treaty positions before you apply them.

Where to claim the deduction

The deduction is claimed in the annual income tax return, in the section for international double taxation. It is not claimed in your quarterly returns, although the income is included in them. For the full set of returns, see taxes for freelancers with foreign clients in Spain.

Common mistakes to avoid

Declaring only the net amount received instead of the gross income.
Not keeping the withholding certificate.
Forgetting to claim the deduction.
Assuming Spain will refund tax that exceeds the Spanish limit.
Claiming a treaty benefit that does not apply.
Not converting the tax withheld to euros at a documented rate.

Frequently asked questions about double taxation

What is double taxation?

It is the situation where two countries tax the same income. Treaties and domestic rules try to avoid it.

Does Spain tax foreign income?

Yes, for tax residents. You declare worldwide income and can claim a deduction for foreign tax paid, within limits.

Where do I claim the deduction for foreign tax?

In the annual income tax return, in the section for international double taxation.

Do I get a refund if the foreign tax is higher?

Spain generally limits the deduction to the Spanish tax on that income. Any excess may need to be recovered from the foreign country.

What proof do I need?

A certificate or statement of the tax withheld, proof of payment where requested, and your invoice and payment records.

Do most freelancers face double taxation?

Not usually. Services performed from Spain for foreign clients are generally taxed in Spain only, but exceptions exist.

Final thoughts on double taxation

Double taxation is rarely a problem for freelancers who work from Spain, but it is worth knowing the tools: treaties to reduce tax at source, residence certificates to prove your status and the foreign tax credit in your annual return. Check withholding before you sign, keep your certificates and declare gross income. With those habits, double taxation will not erode your fees.

Sources and further reading

Related guides

Disclaimer: This article is for general information only and is not tax, legal or financial advice. Rules, fees and thresholds change often and differ by country; always confirm current details with the tax authority and a qualified adviser. Some links may be affiliate links, which means we may earn a commission at no extra cost to you.

Double Taxation: How Freelancers in Spain Avoid Paying Tax Twice on the Same Income