Capital gains or self-employed income.
Capital gains: 19% - 25,75% Income tax: 0% - 49,75%
Taxable only when exchanged back into FIAT.
Professionals have to make advanced payments.
Included in annual personal income tax return.
In essence, cryptocurrencies shall be taxed in a similar way to foreign currencies; that is, on one hand, they are exempt from VAT because they are considered a means of payment, and on the other hand, the income derived from trading with them will be taxed as capital gains in the Spanish Personal Income Tax.
Bitcoins in Personal incoming tax
In terms of Spanish Personal Income Tax (SPIT), Bitcoins are treated like any other foreign currency. The consequence of this is that each time a Bitcoin is transferred by the taxpayer (e.g., because the taxpayer sells Bitcoins or buys another asset paying with Bitcoins), a capital gain or loss will be generated in terms of SPIT. Note that capital gains or losses shall be calculated as the difference between the transfer price and the acquisition cost. If a transfer of Bitcoins derives in a capital gain, it will be taxed at a progressive tax rate ranging from 19 percent to 23 percent, depending on the total amount of savings income subject to taxation.
Disclaimer: This is not a legal, tax, accounting or investment advice. It is general information which should only be used for introduction purposes. You should consult with a tax/legal specialist.