Spain’s income tax campaign has only just opened, but one figure already jumps out. The Tax Agency expects to collect €24.628 billion from returns that end up payable, with around 7.7 million taxpayers expected to owe money when they file. That does not mean most people will be hit with a bill, but it does point to a campaign in which the state expects a much stronger take from those whose finances improved in 2025.

The reason matters. This is not simply a story about wages creeping up. Spain’s tax authorities have linked the sharp rise in capital gains returns to a surge in capital gains, especially from property sales and shares, after a year in which housing values and financial markets both moved strongly. In other words, people who sold assets at a profit in 2025 are far more likely to feel it now.

A bigger tax take, even though refunds still dominate

Most returns will still go the other way. The Agencia Tributaria expects to receive about 25.25 million declarations in total this campaign, up 2.1% on last year. Of those, around 15.7 million are expected to result in refunds worth €13.271 billion. Even so, the amount due from payable returns is forecast to rise much faster, leaving the Treasury with a far healthier net result than in the previous campaign.

Plenty of households will still get money back, but the campaign’s balance is shifting because more people have income streams that do not fit neatly into a simple salary-only return. Selling a flat, cashing in investments, earning rental income or generating gains through other assets can all change the final outcome.

Property and investments are driving the change

The Tax Agency’s own presentation points to rising employment as one reason more declarations will be filed this year. But the more striking change lies in the amount expected from returns that come out payable. According to the agency’s director general, that jump is closely tied to the rise in gains from selling homes and shares, both of which increased in value during 2025.

That helps explain why this year’s campaign may catch some people off guard. Someone whose monthly pay packet felt broadly familiar in 2025 may still face an unexpected bill if they sold property, realised investment gains or had additional income that was not fully accounted for through withholding during the year. It is one more sign that economic growth does not always feel like good news by the time tax season arrives.

Hacienda is watching rentals, crypto and platform income more closely

This year’s campaign also comes with a sharper compliance push. RTVE reports that the Agencia Tributaria plans to send more than 3.5 million warnings to taxpayers who may need to declare income linked to cryptocurrencies or rental property. The official campaign note also says the agency has expanded its preventive messages before filing and added new alerts aimed at stopping people from missing deductions or submitting returns with inconsistencies.

That matters because the pressure is now coming from both directions. Some taxpayers may owe more because they genuinely earned more from property or investments. Others may simply find that the state has better data, better prompts and more ways of flagging areas where a return deserves a second look. The days of glancing at the draft and clicking through without thinking are becoming a riskier habit.

The key dates to keep in mind

The online campaign opened on 8 April 2026 and runs until 30 June 2026. For those who want to pay by direct debit, the deadline is 25 June. Telephone assistance under the ‘Le Llamamos’ service begins on 6 May, with appointments available from 29 April, while in-person help in offices starts on 1 June, with appointments from 29 May.

There are also more payment options than some readers may expect. The official campaign note says payable returns can be handled through the usual online routes and that payment can be made by direct debit, card or Bizum. The Tax Agency also says payment can still be split into two instalments, with the second due on 5 November.

Spain temporary rental tax checks set to tighten in 2026

Why this campaign deserves a closer look

For many taxpayers, the practical lesson is simple. If your finances in 2025 included anything beyond a straightforward salary, this is not the year to rush. The Tax Agency itself highlights common areas that should be checked carefully, including regional deductions, rental property, asset transfers, personal circumstances, subsidies and other aid.

That is why this year’s campaign feels more significant than the usual annual paperwork story. Spain is expecting a much larger intake from payable returns, not because everybody is suddenly richer, but because more people have income, gains or obligations that push them into more complicated tax territory. For some, that will mean a bigger bill. For others, it will simply mean paying closer attention before pressing submit.