Criminal law
Published on 25 June 2026
When the Criminal Code changes, it is tempting to assume that the latest version always governs. It does not. For conduct that has already taken place, the starting point is the law in force when it was committed. There is, though, an important exception in the defendant's favour: if the later law is more beneficial, it applies backwards. This is favourable retroactivity, the lex mitior.
This is brought into focus by Organic Act 1/2026 of 8 April, on habitual reoffending, which amended the Spanish Criminal Code (including articles 22 and 66) and came into force on 10 April 2026. When a reform of this kind affects matters based on earlier conduct, it is worth examining, case by case, which wording applies.
The Criminal Code provides that more favourable criminal laws have retroactive effect, even where a final judgment has been handed down and the person is already serving their sentence; and that, where there is doubt as to which law is more favourable, the defendant must be heard (article 2.2 of the Criminal Code). In practice, this comes down to three ideas:
The 2026 reform affected the aggravating circumstances (article 22) and the rules for determining the sentence (article 66), in particular the treatment of reoffending. Which of the two versions is more favourable cannot be assumed: it has to be checked in each matter, as the reform itself illustrates below.
Take the 2026 reform itself. Someone is tried today for habitual-reoffending conduct committed, say, in January 2026, before Organic Act 1/2026 came into force on 10 April. Even though the trial takes place after the reform, the tougher wording of articles 22 and 66 now in force does not apply to them: the wording that predates the reform still governs, as the more favourable one, because it was in force when the conduct took place.
The rule works the same way in reverse. If a future reform softened that same treatment, someone who had committed the conduct before that reform would equally benefit from the new, more lenient wording, even if a final judgment had already been handed down by then: favourable retroactivity reaches a conviction already given, too.
Which is why, before assuming anything, the two versions need to be compared with care, whichever direction the reform moves in.
This is where method shows. Before settling on a position, I check what the wording of the provision was on the date of the conduct and compare it with the version in force, to see which law applies and whether there is room for lex mitior. I check every citation against its official source, the BOE, and never take one as good without verifying it.
If you have criminal proceedings open over conduct predating a recent reform, the first thing I need to know is the exact date of the conduct: from there I can tell you which wording works in your favour.
Editorial responsibility: Carles Jiménez, attorney-at-law (Barcelona Bar No. 34.946). This note was prepared with the assistance of artificial-intelligence tools and reviewed and approved by the author before publication.
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