Info and Regulations on Operating a Boat in Montana
By angelamontana

Posted: January 3, 2020

Boat Registration

Sailboats 12 feet long and longer and all motorboats and personal watercraft must be registered at the local county treasurers office. Boats from out of state or country which will not be in Montana for more than 90 consecutive days are exempt from registration.Learn more

Operator Age Limit – Motorboats & Personal Watercraft

Children 12 years old or younger may not operate a motorboat or a personal watercraft powered by a motor rated at more than 10 horsepower unless accompanied by someone 18 years of age or older.

Youths 13 and 14 years of age may not operate those vessels without possessing a valid Montana motorboat operator’s safety certificate or evidence of completing an approved boating safety course, or unless accompanied by someone 18 years of age or older.

Rented Boats and Watercraft

A person must be 18 years or older to rent a motorboat or a personal watercraft powered by a motor rated at more than 10 horsepower. All required equipment and a copy of the rental agreement must be on board rented vessels.

Water Skiing and Using Other Towed Devices

  • Water skiing and other towed recreation is not allowed between sunset and sunrise.
  • There must be at least two people in the towing boat: an operator and a person to observe the skier. If the operator is 12 or younger, the observer must be at least 18.
  • Anyone towed by a boat must wear a U.S. Coast Guard approved PFD.
  • Water skiers must not approach within 50 feet of swimmers or enter a designated swimming area.

Personal Watercraft: Jet Skis, Water Bikes, Etc.

  • All operators and riders must wear U.S. Coast Guard approved PFD.
  • If the personal watercraft is equipped with a lanyard-type cord that shuts off the engine if the operator falls off the craft, the lanyard must be attached to the operator’s wrist or PFD.
  • A “no wake” speed must be maintained when within 200 feet of a dock, swimmer, swimming raft, non-motorized boat, or anchored vessel.
  • Stand-up personal watercraft and personal watercraft towing a waterskier must travel at the minimum speed necessary to operate when leaving from or returning to a dock or shore.
  • All rules regarding safe operation of a boat apply to personal watercraft as well.
  • For more regulations and tips read Personal Watercraft Brochure 220 KB

Alcohol and Drug Use

It is unlawful to operate or be in actual physical control of a motorboat, sailboat, water skis, surfboard, or similar device attached to a motorboat while under the influence of alcohol or drugs. A person with an alcohol concentration of 0.08 or more is considered under the influence of alcohol. [MCA 61-8-4]

Negligent Operation

Operating a vessel in a manner which may endanger the personal health or damage the property of any person is considered negligent operation. A boat’s owner is liable for any injury or damage resulting from negligent operation.

Montana law prohibits:

  • operating a boat in a careless manner including such things as weaving through congested traffic, passing unreasonably or unnecessarily close to another vessel, and buzzing or wetting down others
  • crossing or jumping the wake of another boat within 100 yards of the vessel or within 100 yards of a water skier being towed by the vessel (except when directly entering or leaving a marina or other watercraft docking/loading area)
  • travel at a speed which does not permit bringing the boat to a stop within the assured clear distance ahead
  • a reckless approach to, departure from, or passage by a dock, ramp, diving board, or float

Observe all “no wake” and speed-limit signs located on the water. Boaters are responsible for any damage caused by their wake.

Restricted Areas – General

  • Do not anchor in a position that obstructs a passageway ordinarily used by other vessels.
  • Do not operate your boat within 20 feet of the exterior boundary of a designated swimming area marked by white and orange buoys.
  • Do not operate a boat within 75 feet of a person engaged in fishing or hunting waterfowl unless it is unavoidable. If unavoidable travel at no wake speed or at the minimum speed necessary to maintain upstream progress.
  • Do not operate a motorboat within 200 feet of a tow-float or buoy displaying a red flag with a white slash indicating a “diver down” except by use of sailor oar. In an emergency or if there is insufficient water on either side to avoid passing through the 200-foot safety zone, do not exceed the “no wake” speed. (Note: the burden of proof of the necessity of passing through the safety zone is on the boat operator.) See Diver Down Flag Warning.
  • Do not operate or beach your motorboat within a designated swimming area.
  • Do not operate your motorboat within 50 feet of a swimmer in the water except for boats towing water skiers.
  • Some lakes and rivers have closures and public use restrictions.Learn more

Harassment of Wildlife

Powerboats, sailboats and boats under sail may not be used to kill, capture, take, pursue, concentrate, drive, or stir up any upland game birds, game, or fur-bearing animals. Motor- driven vehicles may not be used to drive, molest, flush or harass any game animal or game bird while hunting.

Launching and Mooring

Boats must be launched from established launching areas if provided. Boat owners should prepare their vessel for launching before parking at the boat ramp, should launch the vessel quickly, and move the tow vehicle so that others may use the area.

Boats may not be left unattended while moored or attached to a public boat dock. Docks are to be used only for loading and unloading unless otherwise posted.

Discharge of Waste

It is illegal to discharge any garbage, refuse, waste, or sewage into or near the water. Boats equipped with toilets or porta-potties must dispose of waste properly. Because there are so few marine pumpout stations in Montana, boaters should check on the local availability of waste disposal stations before using their on-board facilities.

Motor Size

It is illegal as well as unsafe to overpower a boat. The U.S. Coast Guard Capacity Plate on each boat provides the recommended horse power for that vessel.

Noise Limitations

Motorboats and personal watercraft may not emit noise in excess of 86 decibels measured at a distance of 50 feet. At idle speed, exhaust noise may not be in excess of 90 decibels measured one meter from the muffler.

More restrictive noise standards are in effect for Flathead Lake (Flathead and Lake Counties), Echo Lake (Flathead County) and Swan Lake (Lake County) because of population density and heavy recreational use. On these waterways, a person may not operate a motorboat or personal watercraft in proximity to the shore-line if the noise emitted is greater than 75 decibels measured at shoreline in accordance with the shoreline sound level measurement procedure.

Certain exceptions are made for state-sanctioned regattas or boat races and by special permit.

Races, Regattas, and Other Marine Events

Written permission from Montana Fish, Wildlife & Parks is necessary to conduct a boating race, regatta or other marine event on Montana’s waters. Letters of application must be sent at least 30 days prior to the scheduled event. Mail to: Montana Fish, Wildlife & Parks, Boating Law Enforcement, P.O. Box 200701, Helena, MT 59620-0701.

Diver Down Flag Warning

Diver down poster.Boaters must stay at least 200 feet away from a “diver down” flag. If a boat must approach this warning flag, it must do so at a “no wake” speed.

The commonly used diver down warning flags are:

  1. the blue and white International Code Flag “A” (alpha)
  2. a red flag with a diagonal white stripe Diver’s Flag

Accidents, Collisions, and Casualties

Boating accident reports 27 KB are required by law and provide valuable information for use in the prevention of future boating accidents. An accident must be reported immediately to the local sheriffs office or game warden if it caused:

  • the death or disappearance of any person
  • an injury requiring medical treatment beyond first-aid
  • property damage in excess of $100

The operator of a boat involved in a collision, accident, or other casualty must:

  • render practical assistance, without putting self or others in danger, to persons affected by the accident
  • give his or her name, address and identification of the boat in writing to any person injured and to the owner of any damaged property.

Boating accident report forms are available from the county sheriff’s office, game wardens, or any Montana Fish, Wildlife & Parks office.


Authorized officers of Montana Fish, Wildlife &s Parks have peace officer status for enforcement of the boating regulations. Sheriffs, peace officers, and U.S. Coast Guard law enforcement officers also have authority to enforce these provisions. Fish, Wildlife & Parks wardens are authorized to stop, halt, or inspect vessels in order to enforce the laws of this state.


A person convicted of violating Montana’s boating laws or regulations may be fined up to $500 and sentenced for up to six months in jail.

(Info via MT FWP)
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