Golden Bitcoin coin floating above a translucent ledger with decorative columns of figures and an official wax seal, against a dark background with Japanese candlesticks
Original illustration generated with AI (Adobe Firefly) — does not represent real data. Decorative iconography, unrelated to the real Modelo 721 figures cited in the article.

Bitcoin Taxes in Spain: Self-Custody, Modelo 721, and What You Actually Owe

NodeWitness Team 8 min read

Selling Bitcoin for euros isn't the only taxable operation — swapping it for another cryptocurrency is too. And Modelo 721, the obligation that causes the most confusion, doesn't depend on how much you hold: it depends on who custodies your keys.

Bitcoin isn't invisible to tax authorities in Spain, and most of the confusion around it is about when it's taxed and under which obligation, with little doubt over whether it is. Most English-language coverage of the topic comes from crypto tax software with a calculator to sell, or from relocation-focused legal sites writing for foreign residents. This guide sticks to the rules as Spain's tax agency and the Official State Gazette (BOE) publish them, with every official source listed at the end. It maps the problem, and it isn't a filed tax return or a sales pitch.

What events trigger a tax obligation

Three operations generate a taxable gain or loss: selling Bitcoin for euros or another fiat currency, swapping it for another cryptocurrency, and using it to pay for goods or services. Simply buying and holding creates no obligation at all — the obligation arises at the moment of transfer, not from holding. This article builds on the same custody decisions already covered in the general guide to managing your Bitcoin, because where you keep your Bitcoin shapes much of what follows.

Capital gains: how much you pay and on what

Gains from selling or swapping Bitcoin are added to the IRPF savings tax base, under a progressive scale with five brackets: 19% up to €6,000, 21% from €6,000 to €50,000, 23% from €50,000 to €200,000, 27% from €200,000 to €300,000, and 30% above €300,000. You only pay on the gain (sale price minus purchase price), not on the total amount sold — a distinction that's easy to lose track of [1][2].

FIFO: which units count as sold first

If you bought Bitcoin at different times and different prices, and sell only part of it, the tax authority doesn't let you choose which units you're selling: FIFO (First In, First Out) applies — the first units you bought are treated as the first ones sold. This matters especially if you bought part near a cycle top and another part much cheaper: the sale order the tax authority assumes may not be the one that suits you best, and it isn't negotiable.

Modelo 721: the most common misunderstanding

If you control your own Bitcoin private keys, Modelo 721 doesn't obligate you to anything, regardless of the amount — the obligation comes from the custodian, not from how much you hold. It only applies to crypto held by a third party outside Spain (a foreign exchange, for example), and only above €50,000 in total value as of December 31. In later years, you only need to file again if the balance grows by more than €20,000 compared to the year you last filed. The filing deadline is March 31 of the following year [3][4]. This distinction gets lost even in guides written specifically for foreign residents in Spain, which often lead with the €50,000 threshold without clarifying up front that self-custody sits outside the obligation entirely.

Diagram with two columns: Self-custody (hardware or software wallet, your own private keys, NO obligation regardless of amount) and Foreign exchange (third-party custody outside Spain, YES obligation above €50,000)
Original diagram: Modelo 721 depends on who custodies, not on holding Bitcoin itself. Figures sourced from Agencia Tributaria.

Key dates

  • January. Providers with a reporting duty file Modelos 172 and 173 for the previous year [5].
  • January 1 to March 31. Modelo 721 for the previous year, if it applies to you [3][4]. The return for 2026 is due by March 31, 2027.
  • By September 30, 2027. EU tax authorities make their first DAC8 exchange of data with each other, covering 2026 [8]. Each country sets its own deadline for providers to report to its tax authority.
  • 2027, 2028 and 2029. First CARF exchanges, depending on the jurisdiction [9].

The filing window for 2026 income tax returns hasn't been published, so it isn't listed here.

DAC8 and CARF: why this no longer depends only on you declaring it

Spain's tax agency was already getting crypto data from local providers before DAC8. Firms resident in Spain, and foreign firms with a permanent establishment there, that hold private keys for their customers file Modelo 172 each January, listing every customer's balance in each virtual currency on December 31 along with its euro value [5][6]. Firms that exchange virtual currencies for euros or for other virtual currencies, or broker those trades, also file Modelo 173, covering the year's purchases, sales, swaps and transfers [5][6]. Both were filed for the first time in January 2024, covering 2023 [5]. For tax year 2025, the Modelo 173 window ran from January 1 to February 2, 2026 [7].

On top of that, since January 1, 2026 the EU's DAC8 directive requires crypto-asset service providers operating in the EU to collect data on their users. EU tax administrations must exchange the 2026 data within nine months of year-end, by September 30, 2027 [8]. Each country sets an earlier deadline for providers to report to it. In practice, the Spanish tax agency can receive that data from the exchange whether or not you file Modelo 721 yourself.

Outside the EU, the OECD's Crypto-Asset Reporting Framework (CARF) does the same job. Its official list of committed jurisdictions, last updated September 14, 2026, rolls it out in waves [9][10].

  • 46 jurisdictions, Spain among them, start exchanging in 2027, the same timeline as DAC8.
  • 27 jurisdictions, including Switzerland, the UAE, Singapore and Hong Kong, start in 2028.
  • 4 jurisdictions start in 2029: Argentina, Azerbaijan, Mexico and the United States.
  • 4 jurisdictions, El Salvador, Georgia, India and Vietnam, are flagged as relevant and have yet to commit.

If you aren't resident in Spain but use a non-EU exchange, this timeline is what sets your own exposure, so check your jurisdiction against the list. None of these dates change what you owe. They only decide when that information starts reaching a tax authority through a channel you don't control.

Offsetting losses: the part almost no one takes advantage of

Capital losses in a year are netted against that year's capital gains, and any excess carries forward against gains over the next four years, with a 25% cap when offsetting against interest or dividends [1]. How to use that before year-end is covered in tax-loss harvesting bitcoin in Spain. When you choose to realize that gain or loss isn't just bookkeeping: it's a strategic lever in its own right, because every sale you put off is a tax bill you defer with it.

What an automated tool can — and cannot — estimate

Deliberately, this guide doesn't include a calculator. Crypto tax software built for exactly this situation — Koinly, CoinTracker, Blockpit, TokenTax, Awaken, among others — will read a wallet's transaction history, apply FIFO, and hand you a finished number. That's a real product, and for someone with dozens of trades spread across several exchanges it can be worth paying for. What none of them fully solve, and what we won't pretend to solve here either, is telling apart an actual buy or sell from a transfer between your own wallets (see the custody comparison for the different ways your Bitcoin can end up spread across wallets) — a mistake there isn't a minor bug, it's a wrong figure in a real tax filing. Publishing a calculator without being able to guarantee that distinction would break the rule we already follow across the whole project: no text (and no figure) promises something the system can't verifiably deliver.

What to do with this now

  • Identify which operations you carried out this year: sales, crypto-to-crypto swaps, or payments in Bitcoin — all three are taxed the same way.
  • If you hold crypto on a foreign exchange, calculate the total value as of December 31 to see if you're above the Modelo 721 threshold.
  • Keep a record of your losses from prior years, not just this year's gains.
  • For any figure that goes into your actual tax return, check it with a tax advisor — this guide is the map of the problem, not a completed filing.
  • If Bitcoin is part of a years-long horizon rather than a months-long one, that also shapes how you treat it as a long-term plan, not just how you report it the year you sell.

Before calculating anything, it helps to know exactly which operations actually show up in your addresses. You can analyze any of yours with the address analyzer, or see the rest of our market and tax coverage.

Sources

  1. Spain, Law 35/2006 on personal income tax (IRPF), consolidated text, arts. 46, 49, 66 and 76, BOE-A-2006-20764. (Primary)
  2. Agencia Tributaria, IRPF 2025 practical manual, savings-base tax rates (Spanish). (Primary)
  3. Order HFP/886/2023, Modelo 721, BOE-A-2023-17429. (Primary)
  4. Agencia Tributaria, Modelo 721 FAQ, filing period (Spanish). (Primary)
  5. Order HFP/887/2023, Modelos 172 and 173, arts. 4 and 8 and second final provision, BOE-A-2023-17430. (Primary)
  6. Royal Decree 1065/2007 (RGAT), arts. 39 bis, 39 ter and 42 quater, BOE-A-2007-15984. (Primary)
  7. Agencia Tributaria, Modelo 173 filing period (Spanish). (Primary)
  8. Council Directive (EU) 2023/2226 (DAC8), art. 8ad, Official Journal text. (Primary)
  9. OECD Global Forum, Jurisdictions committed to implement the CARF, last updated September 14, 2026. (Primary)
  10. OECD, Argentina commits to start automatic exchange of information on crypto-asset transactions by 2029, September 14, 2026. (Primary)

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Last updated: November 1, 2026