Colorado’s AI Act: the Effective Date, and Why It Moved

Most searches for this law are really one question: when does it actually start. The date has moved once already, by a bill passed in a special session, and that fact is more useful than any single date this page could print.

The dates, in order

• 17 May 2024 — signed. Governor Jared Polis signed Senate Bill 24-205, the Colorado Artificial Intelligence Act, creating Part 17 of Article 1 of Title 6 of the Colorado Revised Statutes. Legislative history and the enacted text are on the General Assembly’s bill page. The Governor issued a signing statement at the same time asking the legislature to amend the Act before it took effect — unusual, and the reason everything below happened.
• 1 February 2026 — the original effective date as enacted in 2024. This is the date still printed in a great deal of 2024-vintage commentary, and it is no longer correct.
• August 2025 — delayed. A bill passed in Colorado’s August 2025 special session postponed the effective date to 30 June 2026. The bill carries a special-session number, SB25B-004; its record is at the General Assembly. A regular-session bill numbered SB 25-004 also existed in 2025 and was a different measure, which is a common source of confusion in secondary coverage.

Why it moved

The delay was not a drafting fix. It was the product of an unusually public disagreement about the Act between the branch that passed it and the branch that signed it. Three threads ran through the argument, and they are worth knowing because they predict where any further amendment would land.

The first is scope. The definition of a high-risk system turns on whether the system makes, or is a substantial factor in making, a consequential decision, and businesses argued that “substantial factor” swept in software that merely assists a human decision. The second is the compliance burden on small deployers, which the Act addresses with a fifty-employee exemption that several parties argued was both too narrow and conditioned on terms — no training on your own data — that a modern deployment routinely fails. The third is the absence of any other state operating the same regime: a single-state obligation with a documentation programme attached is a different proposition from a rule the whole country is adopting, and Colorado spent 2025 as an outlier rather than a first mover.

A regular-session attempt to amend the Act substantively did not succeed in 2025. What passed in the special session was the narrower option: move the date, keep the substance, and give the legislature another session to work on it. That is a meaningful signal about stability — a statute delayed to buy amendment time is a statute whose text is expected to change.

What the delay did and did not change

A postponement of an effective date is the narrowest possible intervention, and it is worth being precise about what it left untouched. The duty of reasonable care on developers and deployers is the same duty it was in 2024. The definition of algorithmic discrimination is unchanged. The impact assessment contents, the ninety-day notification to the Attorney General, the three-year retention period, the rebuttable presumption, the affirmative defence, the small-deployer exemption and the exclusive enforcement authority of the Attorney General all survived the delay in the form they were enacted.

What changed is only when compliance is measured from — and one practical consequence of that. Because the impact assessment obligation is annual, the effective date sets the first cycle. A deployer that built its programme against a February date has a schedule that no longer matches the statute; the artefacts are still the right artefacts. Nothing about the substance of the impact assessment or the duty of care needs redoing because of the delay.

It is also worth being clear about what an effective date does to conduct before it. The Act is not retroactive: the Attorney General cannot bring an enforcement action under Part 17 in respect of a deployment that ended before the date it took effect, and no duty in the Act attaches to a decision made beforehand. What does carry across the line is a system still in use on the date — the reasonable care duty applies to it from that morning, with no grandfathering for systems already deployed, which is why the delay bought preparation time rather than an exemption.

And other Colorado law did not pause while the AI Act moved. The Colorado Privacy Act’s right to opt out of profiling in furtherance of decisions producing legal or similarly significant effects has been in force since 2023 and is unaffected by any of this; the AI Act’s consumer notice in fact points at it. The Colorado Anti-Discrimination Act and federal discrimination statutes likewise applied throughout. A company that concluded it had nothing to do until the AI Act arrived was wrong for a reason that has nothing to do with the date.

How to check the current date yourself

This is a page about a moving number, so the most valuable thing on it is the method rather than the number. Three checks, in order of authority.

Start with the codified statute rather than a bill. Part 17 of Article 1 of Title 6 of the Colorado Revised Statutes is the thing that is in force; a bill is only the instrument that changed it. The Colorado General Assembly publishes the Revised Statutes, and the effective-date note that follows the part is authoritative in a way that a bill summary is not.

Then check for amending bills in the current session. Search the General Assembly’s bill search for measures touching sections 6-1-1701 to 6-1-1707. A bill that has passed both chambers but has not been signed is not law, and a bill introduced is not even close; coverage routinely blurs those stages, which is why the legislature’s own status field on the bill page is the thing to read.

Finally, watch for rulemaking. The Act authorises the Attorney General to promulgate rules, and rules can add dates of their own — a compliance date for a designated risk framework, for instance — that sit alongside the statutory effective date rather than replacing it. A cross-state view of how this is moving elsewhere is in the state AI law tracker.