Driving with kids in Montana? Here’s exactly what Montana law requires for car seats and booster seats — the age and weight thresholds, the fines, and the front-seat rules — drawn from the official Montana Department of Transportation and the statute itself, not a blog summary.
Law data last verified against official state sources: October 4, 2026.
Quick answer
Montana (updated October 2025) requires a rear-facing harness seat under age 2, an internal-harness seat for ages 2–4, a harness or booster for ages 4–8, and belts at age 9+ (or 4’9″).
Montana car seat requirements by age and size
| Stage | What Montana law requires |
|---|---|
| Rear-facing | Children under 2 years of age: rear-facing harness seat. |
| Forward-facing | Children ages 2 to 4: rear-facing OR forward-facing internal harness seat. |
| Booster seat | Children ages 4 to 8: forward-facing internal harness OR booster seat. |
| Seat belt only | Age 9 and up, or when 4’9″ tall: adult seat belt. |
Fines and penalties in Montana
Fine: not published on the official state source. Note: .
Front seat rules in Montana
Front-seat rule: not specified in state law. Note: Montana DOT recommends children under 13 ride in the rear seat, but this is guidance, not a statutory mandate.
The official law
- Statute: MCA 61-13-103
- Official source: Montana Department of Transportation
Research note: Law updated by HB 586, effective October 1, 2025 (Montana DOT).
Montana car seat law FAQs
What is the fine for a car seat violation in Montana?
Fine: not published on the official state source. Note: .
When can my child stop using a booster seat in Montana?
Children ages 4 to 8: forward-facing internal harness OR booster seat. Age 9 and up, or when 4’9″ tall: adult seat belt.
Does Montana law require rear-facing car seats?
Children under 2 years of age: rear-facing harness seat.
Can my child ride in the front seat in Montana?
Front-seat rule: not specified in state law. Note: Montana DOT recommends children under 13 ride in the rear seat, but this is guidance, not a statutory mandate.
Where can I read the official Montana car seat law?
Statute: MCA 61-13-103 Official source: Montana Department of Transportation.
Check another state
Driving across state lines? Requirements change at the border — use our interactive car seat law checker to look up any state by your child’s age, weight, and height.
Related state guides:
This page is for general informational purposes only and is not legal advice. Child passenger safety laws change — always verify current requirements with your state’s DMV, highway safety office, or the official statute linked below before making decisions.