I never declared my crypto: how to get straight with the Spanish tax agency (2026)

If you traded cryptocurrencies in earlier years and never declared them, this year you can put things right. You are far from alone: plenty of people bought, sold, swapped between coins or used several exchanges without knowing it could affect their tax return.

The important thing is not to improvise. Getting straight does not mean filing any old number or declaring everything blind. The right order is:

1. Rebuild your complete history.
2. Prepare a tax report with the correct calculation.
3. File the 2025 tax return properly.
4. Check whether earlier years should also be regularised.

Here is the part that surprises people most: even if all you want to declare is this year, preparing this year’s report requires data from earlier years. The reason is the FIFO method that the Spanish tax agency requires for calculating many crypto sales and swaps.

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The main idea: report first, returns afterwards

Before filing anything, you need to know what has actually happened with your crypto.

The tax report is the foundation. Without it you do not know whether you have tax to pay, losses that could be offset, or simply documentation to keep on file.

You may decide not to regularise every year, but you cannot ignore those years when it comes to the calculation. If an old purchase feeds into FIFO, that information is needed even if that year is never corrected.

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What getting straight with your crypto actually means

Getting straight is not only about the 2025 tax return. It means putting your tax position in order for this year and for the earlier years in which you traded crypto, so that the history, the FIFO calculation and the returns all line up with the criteria of the Spanish tax agency.

In practice, the tax report shows you:

• What crypto result belongs to the 2025 tax return.
• What crypto result belongs to earlier years.
• Whether those earlier years need to be regularised with an amended return.

The key is to rebuild the complete activity first. Only then do you decide what to file, what to correct and what documentation is worth keeping.

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Even if you never cashed out to euros, there may be something to review

Many people never declared because they never withdrew money to their bank account. But for the Spanish tax agency that is not what determines whether an obligation exists.

There are transactions that can have tax consequences even if you never converted to euros.

So the question is not only “did I move money to the bank?”, but rather:

did I sell, swap, receive or lose any crypto asset during that year?

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Step 1: check whether you have a crypto element to include

The first filter is not whether you hold crypto, but what you did with it during the year.

Your tax return may have a crypto element if in 2025 you carried out transactions with tax consequences, for example:

• You sold crypto for euros or another currency.
• You swapped one cryptocurrency for another.
• You used crypto to pay for something.
• You received income such as staking, rewards, airdrops or similar.
• You had losses that you want properly calculated.

If you only bought and held, there is normally no gain or loss to include in your income tax return for that purchase.

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Step 2: put together the complete history

Even if all you want to file is this year, you may need information from earlier years.

The reason is the FIFO method: the Spanish tax agency takes the view that you sell first the crypto you bought first.

That is why the complete history is requested. Even if you later decide not to regularise an earlier year, that year may be needed to calculate 2025 correctly.

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Step 3: calculate the whole portfolio

The tax report brings exchanges, wallets and movements into order so that your activity turns into results year by year.

The idea is not to look at each exchange separately. If you have used several platforms, the calculation has to be seen as one whole portfolio, because FIFO applies across the entirety of your activity.

That is what gives you the basis for knowing what goes into 2025 and what may affect earlier years.

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Step 4: file the 2025 tax return

Once the report is ready, whatever belongs in the 2025 tax return can be carried across: the gains, losses or crypto income for the year.

The key point is that the return should come out of the report, not out of a quick estimate from an exchange. If the 2025 calculation depends on old purchases, then your return depends on that history too.

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Step 5: regularise if you need to

With the report finished you can see whether there is anything to correct from earlier years.

You may need to file an amended return, review an informational form, or simply keep the report on hand in case the Spanish tax agency asks.

The aim is not to regularise on a hunch. The aim is to decide with the numbers in front of you.

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Which earlier years may still be open

As a general rule, the Spanish tax agency has 4 years to review a return. The clock starts on the day after the statutory filing deadline ends.

As at the publication date of this article, 28 May 2026, the practical picture for income tax is this:

Tax year	End of the ordinary deadline	General position
2021 tax return	30 June 2022	Generally open until 1 July 2026
2022 tax return	30 June 2023	Open
2023 tax return	1 July 2024	Open
2024 tax return	30 June 2025	Open
2025 tax return	30 June 2026	Still within the filing season

There are important nuances: a notification from the Spanish tax agency can interrupt the limitation period, and cases involving a possible tax offence call for a different analysis. But as a practical rule, if you traded from 2021 onwards, do not assume it is closed without checking.

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Documents needed to prepare the report

To prepare the tax report you do not need to start with old tax returns or notices from the Spanish tax agency. What the report needs, above all, is operational information: where you bought, what you moved, what you sold and what was left on each platform or wallet.

This is the information the tax report is built on. That report is then used to file the 2025 tax return and to decide whether earlier years need correcting.

For an actual filing or regularisation, more documentation may need reviewing:

• Tax returns already filed.
• Letters or notices from the Spanish tax agency, if any.
• Any earlier correspondence relating to crypto, wealth or balances held abroad.

If you are also preparing your return with an accountant, keep your general income tax paperwork separate from the CSV files, API keys and exchange and wallet histories.

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Mistakes to avoid

Calculating the last year only

You may end up filing the 2025 tax return alone, but the calculation should not be made with 2025 alone. If old purchases are missing, FIFO comes out wrong. A 2025 report can depend on purchases made in 2021.

Using only the exchange summary

Summaries are usually not enough. The Spanish tax agency can ask for traceability transaction by transaction.

Ignoring swaps because “there were no euros involved”

Swaps between cryptocurrencies can generate a capital gain or a capital loss.

Not declaring losses

Well-documented losses can help you pay less in future tax years. Ignoring them is not always the prudent choice.

Waiting for the letter to arrive

Regularising before a formal demand usually cuts the tax cost and the penalty risk considerably.

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How we help you regularise your crypto at CryptoImpuestos

Our process is built for people whose history is not clean, or who have been trading across several places for years.

Step	What we do
1. Diagnosis	We review years, exchanges, wallets and any forms that may be affected
2. Extraction	We guide you through downloading CSV files or connecting read-only API keys
3. Tax report	We merge exchanges and wallets, apply FIFO and calculate the result
4. 2025 tax return	We give you the figures you need to declare this year correctly
5. Earlier years	We assess whether amended returns or corrected forms are advisable
6. Report delivery	We leave you a report that stands up to a review by the Spanish tax agency

The critical part is that we do not calculate “just this year” if the earlier history affects the result. First we rebuild the activity, then we decide what to file.

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Conclusion: the crypto element, the report and then the filing

If you did not declare crypto in earlier years, do not start by filing approximate figures. First check whether you have crypto transactions to include in your tax return and rebuild your history with a FIFO tax report.

With that report you can file the 2025 tax return correctly and decide, with the numbers in front of you, whether it is worth regularising earlier years.

The sooner you do it, the more room you have to come forward voluntarily and the less you depend on reacting in a hurry to a letter from the Spanish tax agency.

At CryptoImpuestos we can help you rebuild your activity, prepare the tax report, file this year and review the regularisation of earlier years.

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Official sources consulted

• AEAT: buying and selling virtual currencies for income tax purposes
• AEAT: filing deadline for Modelo 721
• BOE: General Tax Act 58/2003, limitation periods and surcharges