Montana DUI Laws and Penalties (2026)
A complete guide to DUI and DWI laws in Montana, including penalties for first and repeat offenses, BAC limits, license suspension rules, and when a DUI becomes a felony.
Montana DUI At a Glance
First Offense DUI in Montana
24 hours–6 months jail, $300–$1,000 fine, 6-month suspension
Montana requires addiction counseling for repeat offenders
Second Offense DUI in Montana
7 days–1 year, $600–$2,000 fine, 1-year suspension
When Does a DUI Become a Felony in Montana?
In Montana, a DUI typically becomes a felony charge at the 3rd offense. Additional circumstances that can elevate a DUI to a felony include:
- Causing injury or death to another person while driving impaired
- Having a child passenger in the vehicle
- Having an extremely high BAC (typically 0.15% or 0.16%+)
- Driving on a suspended or revoked license due to a prior DUI
Montana DUI BAC Limits
| Driver Type | BAC Limit |
|---|---|
| Standard (21+) | 0.08% |
| Under 21 | 0.00%–0.02% (zero tolerance) |
| Commercial Driver (CDL) | 0.04% |
Refusing a Breathalyzer in Montana
Montana, like all U.S. states, has an implied consent law. By driving on Montana roads, you implicitly consent to chemical testing (breath, blood, or urine) if lawfully arrested for DUI. Refusing a test will typically result in automatic license suspension, separate from any DUI conviction, and the refusal can be used against you in court.
DUI vs. DWI in Montana
Different states use different terminology. Montana uses DUI (Driving Under the Influence) as its primary statute, though both alcohol and drug impairment can result in charges.
Finding a DUI Lawyer in Montana
If you are facing a DUI charge in Montana, it is strongly recommended to consult with a qualified DUI defense attorney as soon as possible. An attorney can:
- Review the circumstances of your arrest for procedural errors
- Challenge the accuracy of BAC testing equipment
- Negotiate for reduced charges or alternative sentencing
- Represent you at DMV hearings to contest license suspension