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Register Boats

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.

Display of boat numbers and decals

View the quick reference on Understanding Montana's Required Boat Decals 277 KB

Permanent decal

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

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

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 Fish, Wildlife & Parks regional/area offices or online:

Green validation decals will expire February 29, 2020. New validation decals are red and will be in effect for another 3-year period expiring February 28, 2023. Boat owners should remove each green decal or cover it with the new red decal.


Permanent Registration

Under MCA 61-3-321, all motorboats, personal watercraft, motorized pontoons and sailboats 12 in length and longer must be permanently registered.

Certificate of Ownership (title)


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


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


All Motorboats, Motorized Pontoons and Sailboats 19 feet in length and longer