All states have laws against boating under the influence (BUI), which make it a crime to operate a boat or watercraft on a public waterway while under the influence of alcohol or drugs.
In Montana, operating a boat or other watercraft while under the influence of alcohol or drugs is illegal, similar to driving a vehicle under the influence (DUI). Montana's BUI laws are outlined in the Montana Code Annotated (MCA) 23-2-523. It is unlawful for a person to operate a motorboat or a sailboat on the waters of the state if they have a blood alcohol concentration (BAC) of 0.08% or more, or if they are under the influence of alcohol, drugs, or a combination of the two, to a degree that the person is incapable of safely operating the watercraft. Penalties for BUI in Montana can include fines, jail time, and the loss of boating privileges. Additionally, Montana law requires mandatory boater education for certain individuals, which includes information on the dangers and legal consequences of BUI.