The deadline is what catches people
You can satisfy every condition of the impatriate regime — arrived from abroad, right kind of job, not a footballer — and still lose it. Not because you didn't qualify, but because you filed the paperwork a week too late.
You have 6 months to file form 149 (modelo 149), counted from the start date of activity shown on your Spanish Social Security registration.
Why it is so easy to miss
Nobody sends you a reminder. There is no letter, no email, no warning in your payroll. The clock starts on a date that is buried in your Social Security paperwork, and most people moving countries have forty other things on their mind in month one.
By the time your first Spanish tax return comes around — which is the moment most people start thinking seriously about tax — the window has usually closed. And the regime is worth six years of savings, so the mistake is expensive.
When the clock starts
From the start-of-activity date shown on your Spanish Social Security registration. Not from the day you landed, not from the day you signed your contract, and not from the day you got your NIE — although in practice these often fall close together.
If you are on the posted-worker route rather than a Spanish payroll, it runs from the equivalent documentation from your employer's home authority. This is exactly the kind of detail worth paying a professional to confirm rather than guessing at.
What happens if you are late
Filing outside the window can block you from the regime even when you meet every other requirement. That is the whole reason this page exists.
That said: do not conclude on your own that it is lost. Deadlines of this kind sometimes have more nuance than a summary page can carry, and how the tax agency treats a given case is not something a calculator can tell you. If your date has passed, that is a reason to speak to a tax professional quickly, not a reason to give up.
Work out your own date
The eligibility check asks for your Social Security registration date and works out the deadline, including how many days you have left.
The 6-month window comes from the Personal Income Tax Regulation (article 116) and is stated consistently by every Spanish tax professional we checked. It is the one figure on this site we could not confirm on a page of the tax agency's own website, because their public pages describe the regime without stating the filing window. We would rather tell you that than pretend otherwise. Confirm your specific date with a professional.
What the regime is worth, so you know what is at stake
24% flat on work income up to €600,000, for 6 tax years. For someone earning €80,000 in Catalonia that is roughly €8,000 a year, or around €48,000 across the full run. Run your own numbers.