Uninsured motorist coverage rules in Arizona

If the driver who hit you carried no insurance, too little insurance, or drove off without stopping, the money for your injuries often has to come from your own policy. In Arizona that money is uninsured motorist (UM) and underinsured motorist (UIM) coverage. The general idea is the same everywhere, so this page sticks to what Arizona does differently: who has to offer the coverage, how you turn it down, how much you can collect, and how long you have to act.

You don't have to buy it, but your insurer has to offer it

Arizona does not require you to carry UM or UIM coverage. It does require every insurer writing an auto liability policy in the state to offer both coverages to you in writing. Under A.R.S. § 20-259.01, that offer must be made "by written notice," and the coverage has to be available at limits at least equal to the bodily injury liability limits already on your policy.¹ You can take it, buy less than your liability limits (down to the state floor), or reject it, but any rejection has to be in writing. If you never signed a written rejection, a court can read UM/UIM into the policy at limits matching your liability coverage.¹

Because UM/UIM pays for bodily injury, the minimum if you elect it is 25/50: $25,000 per person and $50,000 per accident.² Those are the same bodily injury figures Arizona sets for liability coverage. The full state minimum has been 25/50/15 ($25,000 per person and $50,000 per accident for bodily injury, plus $15,000 for property damage) on every policy issued or renewed on or after July 1, 2020.³

Uninsured and underinsured are not the same coverage

The two solve different problems. Uninsured motorist coverage applies when the at-fault vehicle has no bodily injury liability policy meeting Arizona's minimums, and it also reaches a car whose insurer has become insolvent and can't pay.¹ A hit-and-run driver who is never identified is treated as uninsured, which is why UM still matters when you never learn who hit you.

Underinsured motorist coverage is narrower. It applies when the at-fault driver does have insurance, but the total liability limits available are less than your damages.¹ You collect the other driver's liability limit first, and UIM fills the gap up to your own UIM limit. A badly injured person who recovers only $25,000 from the at-fault side can still turn to a larger UIM policy for the rest.

The three-year deadline that catches people

This is the rule most people get wrong. A personal injury lawsuit against the driver who hit you has to be filed within two years of the crash under A.R.S. § 12-542.⁴ A UM or UIM claim is different. It is a claim against your own insurer under your contract, and it runs on its own clock under A.R.S. § 12-555.⁵

That statute gives you three years, and it works in two steps. First, you have to give your insurer written notice of your intent to pursue the claim within three years of the accident, or within three years of when you knew or should have known the other driver was uninsured or underinsured.⁵ Second, after that notice, you have to demand arbitration or file suit within three years of giving it.⁵ Miss either step and the statute says the insurer is not liable for UM or UIM benefits at all.⁵ The longer contract clock can be deceptive: the two-year tort deadline against the at-fault driver may run out first, and settling with that driver too quickly can undercut a later UIM claim. Tell your own insurer early.

Stacking more than one policy

If your household owns several vehicles, you might expect to add up the UM/UIM limits across every policy. Arizona lets insurers block that. Under § 20-259.01(H), when multiple policies or coverages bought by one insured on different vehicles apply to a single accident, the insurer may limit recovery to just one policy, chosen by the insured.¹ Whether any stacking is allowed depends on the exact wording of the policy.

The Arizona Supreme Court tightened this in 2026. In State Farm Mutual Automobile Insurance Co. v. Balzan, decided July 6, 2026, the court held that people who jointly buy insurance count as "one insured" under the anti-stacking statute, so a set of household policies could be capped instead of piled one on top of another.⁶ The practical point for a crash victim: don't assume every policy under the roof adds together. What you can collect depends on who bought which policy and what the anti-stacking clause says.

Your own share of fault still counts

Arizona is a pure comparative negligence state under A.R.S. § 12-2505.⁷ Your recovery drops by your percentage of fault, but it is never eliminated, even if you were mostly to blame. This carries into UM/UIM claims, because your own insurer effectively stands in for the uninsured driver and can argue you were partly responsible. If a UM adjuster assigns you 30% of the fault, expect the payout to fall by roughly that much.

Med-pay, the $5,000 rule, and your car

Medical payments coverage (med-pay) is a separate optional add-on, not something your insurer must offer the way it must offer UM/UIM.¹ It pays medical bills no matter who was at fault. Arizona also limits how far your insurer can reach into your recovery to get that money back: for crashes after December 31, 1998, a med-pay reimbursement lien reaches only amounts over $5,000, so the first $5,000 in benefits is protected.¹

One thing UM/UIM does not do in Arizona is pay for your vehicle. The coverage is for bodily injury, not property damage, so a damaged or totaled car from an uninsured driver is a separate issue, usually handled through your own collision coverage. If your car lost resale value even after a correct repair, see our guide to diminished value claims in Arizona.

Proving that the other driver was uninsured

Whether the other driver had no coverage, too little, or fled, you have to document it. The crash report for your Arizona collision is usually the record that fixes who was involved and what insurance they carried, and notifying your own insurer early keeps you clear of the § 12-555 notice deadline.⁵ UM/UIM disputes turn on policy language, stacking clauses, and comparative fault, and your insurer is the party on the other side of them, so many people have a lawyer look at the file before signing anything. You can find a personal injury attorney who handles Arizona UM and UIM claims.

This article is general information, not legal advice.

Sources

Arizona Revised Statutes § 20-259.01 (uninsured and underinsured motorist coverage). https://www.azleg.gov/ars/20/00259-01.htm
Arizona Department of Insurance and Financial Institutions, Automobile Insurance (consumer information). https://difi.az.gov/consumer/automobile-insurance
Arizona Revised Statutes § 28-4009 (minimum motor vehicle liability coverage limits). https://www.azleg.gov/ars/28/04009.htm
Arizona Revised Statutes § 12-542 (two-year limitation for personal injury actions). https://www.azleg.gov/ars/12/00542.htm
Arizona Revised Statutes § 12-555 (limitation on uninsured and underinsured motorist claims). https://www.azleg.gov/ars/12/00555.htm
State Farm Mutual Automobile Insurance Co. v. Balzan, No. CV-24-0140-PR (Ariz. July 6, 2026). https://www.azcourts.gov/Portals/0/OpinionFiles/Supreme/2026/CV240140PR.pdf
Arizona Revised Statutes § 12-2505 (comparative negligence). https://www.azleg.gov/ars/12/02505.htm

Uninsured Motorist Coverage Rules in Arizona