Montana Boating Laws – What you need to know


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. 


Motorboat Certificates  

The Montana Fish, Wildlife & Parks boat safety education program offers a home-study course or internet courses for motorboat and PWC operators. Persons 13 years of age or older who successfully complete the course will receive a motorboat operator’s certificate.  

Rented Boats and Watercraft  

A person must be 18 years or older to rent a motorboat or a PWC 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  

  • Anyone towed by a boat (including wake boards) must wear a U.S. Coast Guard approved life jacket.
  • 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.  
  • Water skiers must not approach within 50 feet of swimmers or enter a designated swimming area.
  • Be courteous, minimize repetitive passes on any one portion of shoreline, stay well away from the shoreline & docks, and keep music at reasonable level.  

Personal Watercraft (PWC): Jet Ski, Wave Runner, Sea-Doo  

  • All operators and riders must wear a U.S. Coast Guard approved life jacket.
  • If the PWC 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 life jacket.
  • 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 PWC and PWC 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 PWC.  

Swimming Areas  

Designated swimming areas are marked with white and orange buoys. It is unlawful to deface, disturb, remove or relocate any authorized buoys.  

Alcohol and Drug Use  

It is unlawful to operate or be in actual physical control of a motorboat, PWC, sailboat, water skis, surfboard, or similar device while under the influence of alcohol or drugs.  


Montana and federal laws require that basic safety items be on board all boats and stand-up paddle boards (SUP). Life Jackets and Personal Flotation Devices

  • All recreational vessels must carry one wearable life jacket for each person on Board.
  • U.S. Coast Guard approved life jackets must fit the intended wearer, be readily accessible, and be in good condition.
  • Children under 12 years of age must wear a life jacket on a boat less than 26 feet in length that is in motion.
  • All vessels 16 feet in length and over must have one U.S. Coast Guard approved throwable personal flotation device that is immediately available for use.
  • A speciality/inflatable life jacket may be used in place of any life jacket if specifically approved by the U.S. Coast Guard for the activity in which the wearer is engaged. The inflatable life jacket must be worn at all times to be acceptable. You must be 16 to wear an inflatable life jacket.
  • Personal floatation devices are required to be securely worn when operating a sailboard if: the person operating the sailboard is 14 years of age or younger; or two or more people are occupying the sailboard.  

Life Jacket Labels  

The traditional “Types” on life jacket labels are being replaced by a new labeling system that relies more on icons and less on wording. Older U.S. Coast Guard-approved life jackets and flotation aids labeled by “type” still meet regulatory requirements until no longer in good wearable condition. You will not have to purchase a new life jacket because of this labeling change.  

Both labels will still show the size of the life jacket and that it is U.S. Coast Guard-approved. Life jackets with these new labels will be accepted in the U.S. and Canada.  

New Life Jacket Labels Wearable life jackets will be divided into five buoyancy categories: 50, 70, 100, 150, and 275 Newtons (metric to harmonize with Canadian standards). New life jackets will have a tag attached that will explain the different types of icons and what they mean. Icons will show what activities the life jacket is intended for and if it will turn an unconscious person face up. Old Life Jacket Labels Old labels will have a Type I, II, III, IV, or V. The life jackets intended use will be in writing. 

  • Type I: Wearable Off-shore Life Jacket Best for open, rough or remote waters where rescue may not be immediate. Designed to turn an unconscious person face-up.  
  • Type II: Wearable Near Shore Life Vest Good for calm water where fast rescue is likely. A good choice for children when equipped with a strap to buckle between their legs.  
  • Type III: Wearable Floatation Aid Generally the most comfortable to wear for water sports. Available in many colors and styles including vests and float coats. Will not turn an unconscious person face-up.  
  • Type IV: A Throwable Device — Not Wearable Includes boat cushions, ring buoys and horseshoe buoys. Designed to be thrown to a person in the water and grasped to the chest, not worn.  
  • Type V: A Special Use Device Intended for specific activities. May be used instead of another PFD only if used according to conditions printed on the label. Includes deck suits, pullover vests, work vests and some hybrid life jackets. Not intended for children under age 16.  

Fire Extinguishers  

A fire extinguisher is classified by the type of fire it is meant to extinguish and its size. Extinguishers approved for motorboats are hand-portable of either B-I or B-II classification. A type B extinguisher is intended for flammable liquids such as gasoline, oil and grease fires. All motorboats must carry on board a U.S. Coast Guard approved fire extinguisher as listed below:  

Fire Extinguisher Requirements

Boat LengthWithout fixed extinguishing system in machinery spaceWith fixed extinguishing system in machinery space
Less than 26 Feet*1 B-INone
26 Feet to less than 40 Feet2 B-I or 1 B-II1 B-I
40 Feet to 65 Feet3 B-I or 1 B-II and 1 B-I2 B-I or 1 B-II

* Exception: motorboats less than 26 feet long that are propelled by an outboard motor and are completely open construction (no closed spaces where gasoline fumes may be trapped) are not required to have a fire extinguisher.  

Whistles, Horns and Bells

  • Sirens may not be used or installed except on authorized emergency vessels.
  • A motorboat 16 to 26 feet long must carry some means of producing an efficient sound signal that is audible for one-half mile, such as a whistle or a horn.
  • A motorboat more than 26 feet long must have on board a bell and a whistle or horn capable of making a sound that is audible for one mile.
  • It is advised that all vessels carry a whistle or horn or some other sound signaling device to signal your intentions and signal your position during periods of reduced visibility.  

Maneuvering and warning signals:  

  • One Long Blast: warning signal (coming out of a slip)  
  • One Short Blast: Pass you on my port (left) side Two Short Blasts: Pass you on my starboard (right) side  
  • Three Short Blasts: In reverse  
  • Five or More Blasts: danger signal  

Navigational Lights  

Between sunset and sunrise and at other times of restricted visibility, vessels in operation must display navigational lights. All white lights required by the rules must be visible from a distance of at least two miles. All colored lights must be visible for a distance of at least one mile.  

Navigation lights include:

  • A green light on the starboard (right) side of the boat
  • A red light on the port (left) side of the boat
  • A white light that is visible in all directions (usually located on the stern and higher than the red and green lights)  

Manually propelled (non-motorized) boats may exhibit navigation lights or instead carry a white light which can be exhibited in time to prevent a collision. Boats at anchor outside of a designated mooring area must display an all-around white anchor light between sunset and sunrise.  


These rules of the road are the traffic laws of Montana’s waterways. Like other traffic laws, they are legally binding on vessel operators. The rules dictate who has the right of way when vessels meet in open water and in crowded anchorages.

  • Sailboats and manually powered vessels have the right of way over motorized boats in all situations. Motorboats generally should stay clear of sailboats and manually powered vessels and not create a wake which may cause them trouble or to be swamped.
  • When overtaking another vessel, the boat being overtaken (stand-on vessel) has the right of way and must hold course and speed. The passing boat (give-way vessel) is required to stay clear.
  • When meeting head on, keep to the right. Boats going downstream have the right of way over boats going upstream. Motorized Boat Manually propelled boat
  • When two boats are meeting at right angles, the boat on the right (stand-on vessel) has the right of way. The give-way vessel on the left must slow down and permit the stand-on vessel to pass.
  • Always operate a vessel at a safe speed so that you are able to stop within the assured visible distance ahead or take proper and effective action to avoid collision.  

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.  

Aquatic Invasive Species (AIS)

AIS are non-native organisms like mussels, snails, crayfish, clams, fish, plants and diseases. Aquatic Invasive Species cause harm to watercraft, fisheries and the environment, and can spread rapidly because there are no natural predators or competitors to keep them in check. All motorized and non-motorized watercraft must stop at ALL open inspection stations. Areas subject to search include but are not limited to the exterior of the vessel, livewells, bait buckets, bilges, and trailer. Watercraft found with Aquatic Invasive Species will be decontaminated. Failure to stop at inspection stations could result in a fine of up to $500.  

Montana law prohibits:  

  • Operating a boat in a careless manner, including weaving through congested traffic, passing unreasonably or unnecessarily close to another vessel, buzzing or wetting down others, and riding on the bow, gunwales or transom.  
  • 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).  
  • Traveling 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.  

Harassment of Wildlife  

Powerboats, PWC, and sailboats 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.  

Loading Passengers and Gear  

  • Do not load a boat with passengers or cargo beyond its safe carrying capacity, taking into consideration weather and operating conditions.  
  • Distribute the weight of passengers and gear evenly.  
  • Keep gear low and centered.  
  • Do not stand or make quick, unbalanced movements in small boats.  

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 PWC 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 PWC in proximity to the shoreline 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 and Parks is necessary to conduct a boating race, regatta or other marine event on Montana’s waters.  

Restricted Areas — General   

  • Do not anchor in a position that obstructs a passageway ordinarily used by other vessels.  
  • Do not operate or beach your motorboat within a designated swimming area or within 20 feet of the exterior boundary of a 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 sail or 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.  
  • Do not operate your motorboat within 50 feet of a swimmer in the water except for boats towing water skiers.  

Local and Federal Regulations  

In addition to state boating laws, local government and federal agency regulations may apply to boating  activities in some areas. Contact the county sheriff’s office or the federal agency for the area where you will be boating to find out if any additional regulations are in effect.  

Accidents, Collisions and Casualties  

Boating accident reports 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 sheriff’s 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 game wardens or any Montana Fish, Wildlife and Parks office.  

Diver Down Flag Warning  

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 Down Flag Indicates a person(s) is engaged in diving in the area.  


Authorized officers of Montana Fish, Wildlife & Parks (FWP) 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. FWP 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.  

Backfire Flame Arresters  

Every inboard gasoline engine must be equipped with a backfire flame arrester that is securely attached to the carburetor and in proper working order.  


All boats of closed construction (the engine or fuel compartments are not open to the atmosphere) and which use gasoline as fuel must be equipped with a ventilation system to remove explosive vapors from the bilges of engine and fuel tank compartments. The explosive vapors are heavier than air and accumulate in the bottom of the boat without proper venting, creating an extremely hazardous condition.

Montana requires at least two ventilation intake ducts fitted with cowls or their equivalent to vent bilges and fuel tank compartments. At least one intake duct must be installed so that it extends to the point at least midway to the bilge, or at least below the level of the carburetor air intake. At least one exhaust duct must be installed so as to extend to the lower portion of the bilge. The duct should not be located so that a normal accumulation of bilge water would obstruct it.  

Remember to adequately ventilate your boat before starting it by running your blower for at least 4 minutes — especially after fueling.  


Boat numbers 

The boat number must: 

  • be painted on or attached to each side of the bow of the vessel; 
  • read from left to right; 
  • be vertical block letters at least 3 inches in height; 
  • be a color contrasting with the background color of the boat; 
  • be as high above the water line as practical and still be visible; 
  • be maintained in a legible condition; 
  • contain a space or hyphen separating the “MT” from the number/letter suffix. (Example: MT 1234 AB or MT – 1234 – AB) 

Permanent decal 

The boat owner will receive one permanent registration decal as proof of payment of fees in lieu of tax. The permanent decal must be displayed on the left (port) bow behind the boat’s number. The permanent decal is valid until the current owner sells the watercraft. 

Validation decal 

All motorboats, sailboats, and personal watercraft that are numbered must display two validation decals, one on each side of the boat’s bow behind the boat’s number. 

Validation decals may be obtained, free of charge, at any Montana Fish, Wildlife & Parks regional/area offices or online: 

 Red validation decals will expire February 28, 2023. Boat owners should remove each green decal or cover it with the new red decal. 


Which boats must be registered 

Sailboats 12 feet long and longer and all motorboats and personal watercraft must be registered and numbered. Non-motorized sailboats less than 12 feet long and manually propelled boats, regardless of length, are exempt from registration and taxation. Also exempt are a vessel’s lifeboat and government-owned boats. 

How to register a boat 


Boat owners must obtain a certificate of ownership (title) and certificate of number (registration) and pay all fees to the County Treasurer in the county where the owner resides. The certificate of number must be carried on board the boat and be available for inspection whenever the boat is in operation. Registration fees are based on the length and age of the vessel. 


Boats that are properly registered in another state or country may operate in Montana for up to 90 consecutive days. 

Homemade Vessels 

Homemade boats or boats manufactured before 1972 that require registration must first have a hull identification number. Generally the 12-digit hull identification (HIN) number is on the exterior of the vessel’s transom in the upper-right corner. 

A boat owner may obtain a HIN number from any Fish, Wildlife & Parks regional or area office. The application fee is $5. The boat owner is responsible for permanently affixing the HIN number on the boat and having the boat inspected by a peace officer. 

Permanent Registration 

Under MCA 61-3-321, all motorboats, personal watercraft, motorized pontoons and sailboats 12 in length and longer must be permanently registered. This is done through the County Treasurer’s Office. 

  • Certificate of Ownership (title): $10 
  • All Motorboats, Personal Watercraft, and Motorized Pontoons less than 16 feet in length, and Sailboats at least 12 feet in length but less than 16 feet in length: $65.50 
  • All Motorboats, Motorized Pontoons and Sailboats at least 16 feet in length but less than 19 feet in length, and Personal Watercraft 16 feet in length or longer: $125.50 
  • All Motorboats, Motorized Pontoons and Sailboats 19 feet in length and longer: $295.50 


Lakes 35 Acres or Less
All watercraft operating on public lakes and reservoirs in the western fishing district that are 35 acres or less of surface water are limited to no-wake speed. These lakes have been determined 35 acres or less by means of the 1:100,000-scale hydrography layer within the department’s geographic information system (GIS). 
Lakes Greater than 35 Acres 
All watercraft operating on public lakes and reservoirs greater than 35 surface acres within the western fishing district are limited to no-wake speed from the shoreline to 200 feet from the shoreline. 

The exceptions include: 

  • PWC which must maintain a minimum operating speed to remain upright and maneuver in the water may travel at that minimum operating speed following the most direct route through the nowake zone to and from shore. 
  • Motorized watercraft towing a skier from or to a dock or the shore, except that watercraft must travel the most direct route through the no-wake zone. 


The following closures and public use restrictions are in effect for reasons of public health, safety or protection of property. Only authorized exceptions such as search and rescue, scientific purposes or special events with the director’s prior written approval are exempt. Some waterways have multiple restrictions that apply, so be sure to check all of the following sections for the body of water you plan to use. Other dams not listed here may also be posted for restricted access. 


The following dams are closed to all boating, sailing, floating and swimming or closed to all public access as marked by boat restraining systems or signs. 

  • The following lakes located with the Thompson Chain of Lakes in Lincoln county: 
  • Crystal Lake – Horseshoe Lake 
  • Loon Lake – Lower Thompson Lake 
  • McGregor Lake – Middle Thompson Lake 
  • Upper lobe of Upper Thompson Lake 
  • Echo Lake in Flathead County is limited to a 200 feet from shoreline no wake speed except for the following areas: 
    • (a) the upper three islands in the southwest corner of section 5, approximately 1/4 mile southeast of the entrance of Blackies Bay; 
    • (b) the narrow corridor that serves as the entrance and exit to Blackies Bay located in the northwest corner of Echo Lake; and (c) the narrow corridor that serves as the entrance and exit to Causeway Bay located in the northeast corner of Echo Lake. 
  • Lake Five in Flathead County

For Additional Information please contact: 

Montana Fish Wildlife & Parks 

1420 East Sixth Avenue 
P.O. Box 200701  
Helena, Mt 59620-0701 

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