Assigned number format
Massachusetts assigns numbers in the pattern MS 1234 AB, using the MS prefix. Note that the vessel prefix (MS) is not the postal abbreviation (MA). Massachusetts uses MS as the vessel prefix, not MA.
State Requirement Summary
Massachusetts Boat Registration Number Requirements
Boats registered in Massachusetts display an MS-prefixed number such as MS 1234 AB. Massachusetts uses the MS prefix rather than MA — that difference alone is a common ordering mistake. Massachusetts calls for characters 3 inches high in block / readable characters, reading left to right, contrasting color, positioned each side of the bow / forward half. Our lettering is designed to meet the displayed Massachusetts size and formatting requirements. The state itself issues the validation/expiration decal — we supply the registration-number lettering.
Boat number requirements
Last regulatory review: August 22, 2026
Assigned number example
MS 1234 AB
Massachusetts uses the MS prefix — not MA.
- Minimum character height
- 3 inches
- Lettering style
- Block / readable characters
- Contrast
- Contrasting color
- Spacing / separator
- 2-inch space OR hyphen between letters and numbers
- Reading direction
- Left to right
- Number location
- Each side of the bow / forward half
- Validation decal
- Port side, in line with and 3 inches toward the stern of the registration number
- State agency
- Massachusetts Environmental Police / Mass.gov
What we sell vs. what the state issues: RegistrationDecals.com supplies the registration-number lettering, designed to meet the displayed Massachusetts size and formatting requirements. Massachusetts Environmental Police / Mass.gov issues the official validation/expiration decal — and any separate stickers such as aquatic-invasive-species, mussel-awareness, carbon-monoxide or lake-protection stickers, which are not interchangeable with each other.
Design your MS numbers
Starts with the Massachusetts format (MS 1234 AB). Tap the decal and type your own assigned number exactly as it appears on your certificate of number.
Tap the decal to edit
Decal color
We supply the registration-number lettering, sized to the displayed Massachusetts requirements. Massachusetts Environmental Police / Mass.gov issues the validation decal.
Massachusetts placement diagram
Both sides of the hull carry the number. The grey square marks where the state-issued validation decal goes — port side, in line with and 3 inches toward the stern of the registration number.
- Height: 3 inches, block / readable characters
- Spacing: 2-inch space OR hyphen between letters and numbers
- Location: Each side of the bow / forward half
- Validation decal: Port side, in line with and 3 inches toward the stern of the registration number
Diagram is illustrative. Confirm exact positioning against the instructions issued with your Massachusetts registration.
Official source
Massachusetts Environmental Police / Mass.gov — Primary state agency source. Last verified August 22, 2026 (source check 2026-08-22).
Mass.gov — Register a boatRegistration requirements can change. RegistrationDecals.com summarizes publicly available boating-registration requirements to help boat owners select and display registration numbers. Always compare your registration and decals with the current instructions issued by your state boating or registration agency before applying them to your vessel.
Massachusetts rules in detail
Minimum character height
Massachusetts specifies characters 3 inches high. Measure the character body itself — if the state excludes borders, outlines or shading, decorative trim does not count toward the minimum.
Required lettering style
Block / readable characters, reading left to right. Script, italic and decorative treatments are not what this style describes.
Contrast requirement
Contrasting color. In practice that means dark characters on a light hull and light characters on a dark hull, checked in daylight from the side of the vessel.
Spacing and separator
2-inch space OR hyphen between letters and numbers. Example: MS 1234 AB. Running the groups together with no separation does not match the stated format.
Placement on the hull
Each side of the bow / forward half. Registration must remain clearly legible.
Validation decal placement
Port side, in line with and 3 inches toward the stern of the registration number. The validation or expiration decal is issued by Massachusetts Environmental Police / Mass.gov — RegistrationDecals.com supplies the registration-number lettering only.
Common mistakes
- Ordering MA instead of the MS prefix Massachusetts actually assigns.
- Characters shorter than the stated minimum (3 inches) so they fit inside a narrow accent stripe.
- Using a script, italic or shadowed style instead of block / readable characters.
- Losing the required separation between the groups — 2-inch space OR hyphen between letters and numbers.
- Placing the state validation decal somewhere other than the position Massachusetts describes: port side, in line with and 3 inches toward the stern of the registration number.
Frequently asked questions
What does a Massachusetts boat registration number look like?
Massachusetts numbers follow the pattern MS 1234 AB, using the MS prefix, a numeral group, and suffix letters.
How tall do Massachusetts boat registration numbers have to be?
3 inches, measured on the character itself, in block / readable characters.
What lettering style does Massachusetts require?
Block / readable characters, reading left to right, and contrasting color.
How much space goes between the letters and numbers in Massachusetts?
2-inch space OR hyphen between letters and numbers. Example: MS 1234 AB.
Where do the numbers go on the boat in Massachusetts?
Each side of the bow / forward half. Registration must remain clearly legible.
Where does the Massachusetts validation decal go?
Port side, in line with and 3 inches toward the stern of the registration number. The decal itself is issued by Massachusetts Environmental Police / Mass.gov; we supply the registration-number lettering.
Who regulates boat registration numbers in Massachusetts?
Massachusetts Environmental Police / Mass.gov. Confirm the current instructions issued with your registration before applying anything to your hull. Last regulatory review: August 22, 2026.
Can I order Massachusetts boat registration numbers online?
Yes. Enter your assigned MS number in the designer on this page, pick a color that contrasts with your hull, and we cut a matched port-and-starboard pair and ship it to the 48 contiguous states.
Does Massachusetts use MA or MS on the decals?
MS. Massachusetts-registered vessels display the MS prefix — ordering MA produces the wrong number.
Related guides
Ready to design your MS numbers?
Our designer starts with plain block characters and proper group spacing, so you can see exactly how MS 1234 AB will read on your hull before you order.
Source: Massachusetts Environmental Police / Mass.gov · Primary state agency source · Primary · Source last checked 2026-08-22.
Registration requirements can change. RegistrationDecals.com summarizes publicly available boating-registration requirements to help boat owners select and display registration numbers. Always compare your registration and decals with the current instructions issued by your state boating or registration agency before applying them to your vessel.