Boat VIN Lookup — How HIN Numbers Actually Work

Boats don't have VINs — they carry a 12-character Hull Identification Number (HIN), required by the US Coast Guard on all boats built since 1972. It's stamped on the starboard (right) side of the transom. The first 3 characters identify the manufacturer, followed by the hull serial and date codes. Boat trailers, however, DO have standard 17-character VINs you can decode and check like any vehicle.

Searches for a 'boat VIN' are really searches for the HIN — the Hull Identification Number. It's the marine equivalent of a VIN, but shorter, formatted differently, and looked up through different channels.

This guide explains where the HIN lives, how to read it, what history checks exist for boats, and the one part of a boat purchase where a real 17-character VIN does apply: the trailer.

HIN vs VIN: what's the difference?

The US Coast Guard has required a Hull Identification Number on every boat manufactured or imported since November 1, 1972. It's 12 characters, not 17, and it's permanently affixed to the hull — molded, engraved, or on a tamper-evident plate.

Reading a 12-character HIN (format: ABC12345D404)
Characters	Meaning
1–3	Manufacturer Identification Code (MIC), assigned by the US Coast Guard
4–8	Hull serial number assigned by the builder
9	Month of certification (A=January … L=December)
10	Last digit of the year of certification
11–12	Model year

Where to find the HIN

The primary HIN is on the starboard (right, facing forward) side of the transom, within two inches of the top. On boats without a transom, it's on the starboard side of the hull near the stern. Builders also hide a duplicate HIN somewhere on the interior or under hardware — if the transom HIN looks tampered with, a marine surveyor can locate the hidden one.

You can identify the builder from the first three characters using the Coast Guard's public MIC database.

How to check a used boat's history

There's no single NMVTIS-style national database for boats, so a thorough check combines sources:

State title/registration check: most states title or register powerboats — verify the HIN, owner, and lien status with the state agency where the boat is registered.
US Coast Guard documentation search: vessels over 5 net tons may be federally documented; the USCG vessel documentation database is publicly searchable.
Theft check: ask local law enforcement or the insurer to run the HIN; stolen-boat records are kept in NCIC and insurer databases.
Hurricane/flood salvage: boats totaled in storms are resold at salvage auctions — inspect for repaired hull damage and ask for insurance history.
Hire a marine surveyor for anything with a meaningful price tag — the boat equivalent of a pre-purchase inspection.

The trailer has a real VIN — check it

Boat trailers are road vehicles with standard 17-character VINs, stamped on the trailer tongue or frame rail. Stolen and title-washed trailers are common precisely because buyers focus on the boat and ignore the trailer paperwork.

Decode the trailer VIN free, confirm it matches the trailer's title, and check its history — a $1 report is cheap insurance on a trailer worth thousands.

Bottom line

There's no such thing as a boat VIN — check the 12-character HIN on the starboard transom, decode the builder through the Coast Guard MIC database, and verify title, liens, and theft through the state where the boat is registered. The trailer under the boat does have a real VIN: decode and check it like any vehicle before you buy the package.

Frequently asked questions

Can I look up a boat by VIN?

Boats don't have VINs — they have 12-character Hull Identification Numbers (HINs). Look up the builder via the US Coast Guard MIC database and verify title/lien/theft status through the state where the boat is registered. The boat's trailer does have a standard VIN you can check.

Where is the HIN on a boat?

On the starboard (right) side of the transom, within two inches of the top, on every boat built since November 1972. Builders also place a hidden duplicate HIN inside the hull to deter tampering.

Is there a Carfax for boats?

There's no NMVTIS-equivalent national history database for boats. A proper check combines the state title/registration record, the USCG documentation database for larger vessels, a theft check through law enforcement or insurers, and a marine survey for condition.

How do I tell a boat's year from the HIN?

The last two characters of a modern HIN are the model year, and character 10 is the last digit of the certification year. A HIN like ABC12345D404 decodes to a model-year 2004 hull certified in April 2004.

Should I check the boat trailer separately?

Yes. The trailer is a road vehicle with its own 17-character VIN and title. Decode it free, confirm it matches the paperwork, and run a history check — stolen and title-washed trailers frequently ride under legitimately owned boats.