What Your Boat Registration Number Means and Where to Find It

Your boat registration number is the unique identifier your state assigns when you register a vessel, and it appears on your certificate of registration and on the hull itself

Every registered boat has a registration number — sometimes called a hull number or registration mark — that distinguishes it from every other vessel in your state. This number is issued by your state's fish and wildlife agency, boating division, or motor vehicle department, depending on your state's structure. The number appears on your certificate of registration (the paper document you receive after registering) and must be displayed on the hull of your boat in a specific location and format.

The registration number is not the same as the hull identification number (HIN), which is a manufacturer's serial number permanently affixed to the boat by the builder. Your registration number is what authorities use to track ownership, renewal status, and safety compliance. You will need this number to renew your registration, transfer ownership, file a lien, or report the boat stolen.

Key Takeaways

Your boat registration number is printed on your certificate of registration and must be displayed on the hull in numbers at least three inches tall, usually on both sides of the bow.
The registration number format varies by state — some use letters and numbers, others use only numbers, and the length ranges from four to eight characters depending on where you registered.
You will need your registration number to renew your boat registration, transfer ownership to another person, or file a lien against the vessel.
If you lose your certificate of registration, you can request a replacement from your state's boating authority using your boat's hull identification number or the owner's name and address.

Where the registration number appears on your boat

Your registration number must be painted or permanently attached to the hull on both sides of the bow, positioned so it is clearly visible from the water. The numbers must be at least three inches tall, in a contrasting color to the hull, and in a block or block-style font that is straightforward to read from a distance. Most states require the number to be placed between the bow and the widest part of the boat, and some specify an exact distance from the bow.

If your boat is a canoe, kayak, or other small vessel that does not have a traditional bow, your state's boating authority will have different placement rules — usually on the side of the hull or on a permanent plate attached to the vessel. Check your state's boating handbook or contact your local boating authority for the exact placement and size requirements for your boat type, because violations can result in a citation.

How registration numbers are formatted by state

Registration number format is set by each state and does not follow a national standard. Some states use a format like "CA 12345 AB" (state abbreviation, numbers, letters), while others use "FL1234567" (state abbreviation followed by numbers only). The length typically ranges from four to eight characters total. A few states use a format that includes the year of registration or a county code, though this is less common.

When you receive your certificate of registration, the number will be printed clearly at the top or in a designated field. If you are unsure of your state's format or cannot locate your number, your state's boating division website usually displays examples, or you can call the agency directly with your boat's hull identification number and they will provide it.

Finding your registration number if you have lost your certificate

If your certificate of registration is lost, damaged, or stolen, you can request a replacement from your state's boating authority. You will typically need to provide your boat's hull identification number (HIN), your name and address as the registered owner, and sometimes a description of the boat (make, model, year). Some states allow you to request a replacement online through their boating portal, while others require you to mail a form or visit an office in person.

The replacement certificate usually arrives within two to four weeks, depending on your state's processing time. In the meantime, you may be able to operate the boat if you can show proof that you have requested a replacement — ask your state's boating authority whether a temporary permit or letter of replacement is available. Keep a photo of your registration number or a copy of the certificate in a safe place so you have a backup if the original is lost again.

When you need your registration number

You will need your registration number when you renew your boat registration, which is typically done annually or every two years depending on your state. You will also need it if you transfer ownership of the boat to another person, because the new owner must register the boat in their name and the number may change or remain the same depending on your state's policy.

If you need to file a lien against the boat (for example, if you are a mechanic or marina owed money for services), the lienholder will request your registration number as part of the filing process. If your boat is stolen, report the registration number to the police and your state's boating authority so they can flag the vessel in their database. Insurance companies will also ask for your registration number when you purchase or renew a boat insurance policy.

What happens if your registration number is missing or illegible

If your boat's registration number is faded, damaged, or missing from the hull, you are required to repair or repaint it to remain in compliance with state boating regulations. A boating officer can cite you for a missing or illegible registration number, and you may be required to correct it within a specified time frame (usually 30 to 60 days). The fine for a missing or illegible number varies by state but typically ranges from $50 to $500.

To repair the number, you can paint it yourself if you have the materials and skill, or you can take the boat to a marine service shop or boat dealer who can repaint or re-attach the number to the hull. Before you do the work, verify the correct number with your certificate of registration or by contacting your state's boating authority, because painting the wrong number is a violation and will require correction.

Registration number versus hull identification number

Your boat's registration number and hull identification number (HIN) are two different things and serve different purposes. The HIN is a 12-character code assigned by the boat's manufacturer and is permanently affixed to the hull, usually on the starboard (right) side of the transom or on a plate inside the boat. The HIN identifies the boat's manufacturer, model, and serial number, similar to a vehicle identification number (VIN) on a car.

Your registration number is assigned by your state when you register the boat and is unique within that state. If you move to a different state and re-register your boat, you will receive a new registration number, but the HIN remains the same. When you look up your boat's history or report it stolen, authorities may ask for either number, so it is helpful to know both and keep them in a safe place.

Frequently Asked Questions

Do I need to display my registration number if my boat is stored on a trailer?

If your boat is registered and you operate it on the water, the registration number must be displayed on the hull regardless of whether the boat is stored on a trailer. If the boat is permanently stored and never launched, check your state's rules — some states do not require the number to be displayed on a boat that is not in use, but the number must still appear on your certificate of registration.

What if I register my boat in one state and then move to another?

You will need to re-register your boat in your new state within a specified time frame, usually 30 to 90 days after establishing residency. Your new state will issue a new registration number, and you will need to remove or paint over the old number and display the new one on the hull. Contact your new state's boating authority for the exact timeline and requirements.

Can I choose my own registration number?

Most states do not allow boat owners to choose their registration number — the state assigns it automatically when you register. A few states offer vanity registration numbers for an additional fee, similar to vanity license plates for cars, but availability and cost vary. Check your state's boating website to see if vanity numbers are available in your state.

Is the registration number the same as the boat's name?

No. Your boat's name is what you choose to call it (for example, "Sea Breeze" or "Lucky Strike"), and it can be painted on the hull or displayed on a transom board. Your registration number is the state-assigned identifier and is separate from the boat's name. Both can appear on the hull, but they serve different purposes.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.