Booster seat requirements in Montana
A car seat or booster until age 9.
Montana sets no height or weight that ends the requirement early. Age is the only test.
- Rear facing until
- 24 months
- Seat belt alone from
- age 9
- First offense
- $100
Every figure on this page was read at Mont. Code Ann. §§ 61-9-420, 61-9-423 on 4 October 2026. Read the statute
What the Montana booster seat law says
The stages below are separate rules in the statute, not one rule in steps.
| Rule | Figure | What Montana requires |
|---|---|---|
| Rear facing | under 24 months | Until 24 months (2 years). |
| Car seat or booster | under 9 years | Until age 9. |
| Adult seat belt alone | from 9 years | Lawful from age 9. |
| Penalty | $100 | $100 for a first offense. Condition Section 61-9-423: a fine of not more than $100. It must be waived on proof, given to the charging officer within 7 days, that an appropriate restraint was acquired, provided no earlier violation has already been dismissed that way. |
Where this and size guidance disagree, follow the stricter one. A belt that crosses the neck rather than the middle of the chest is worse protection than a booster even where the statute allows it.
The statute
Montana sets this in Mont. Code Ann. §§ 61-9-420, 61-9-423. Read it at the source.
This is information, not legal advice. A city or county in Montana can set a stricter rule than the state one, and an officer enforces the text of the statute rather than a summary of it. Where this page and the statute differ, the statute is right and this page is a bug.
Where this comes from
- Statute
- Mont. Code Ann. §§ 61-9-420, 61-9-423
- Source
- mca.legmt.gov
- Jurisdiction
- Montana (MT), state law only
- Last reviewed
- 4 October 2026 0 days ago
- Read at the statute
- 4 October 2026
- Signed off by a person
- Not yet
- Amendment history
- Amd. Sec. 2, Ch. 692, L. 2025 (HB 586), carried as current law in the 2025 Code