Assigned number format
Iowa assigns numbers in the pattern IA 3717 ZW, using the IA prefix. Iowa uses a specific FOUR-INCH decal offset.
State Requirement Summary
Iowa Boat Registration Number Requirements
Boats registered in Iowa display an IA-prefixed number such as IA 3717 ZW. Iowa calls for characters 3 inches high in bold BLOCK characters, reading left to right, must contrast with background, positioned forward half of each side, for maximum visibility. Our lettering is designed to meet the displayed Iowa 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
IA 3717 ZW
- Minimum character height
- 3 inches
- Lettering style
- Bold BLOCK characters
- Contrast
- Must contrast with background
- Spacing / separator
- Space or hyphen
- Reading direction
- Left to right
- Number location
- Forward half of each side, for maximum visibility
- Validation decal
- 4 inches toward the stern from the registration number and in line with it
- State agency
- Iowa Department of Natural Resources
What we sell vs. what the state issues: RegistrationDecals.com supplies the registration-number lettering, designed to meet the displayed Iowa size and formatting requirements. Iowa Department of Natural Resources 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 IA numbers
Starts with the Iowa format (IA 3717 ZW). 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 Iowa requirements. Iowa Department of Natural Resources issues the validation decal.
Iowa placement diagram
Both sides of the hull carry the number. The grey square marks where the state-issued validation decal goes — 4 inches toward the stern from the registration number and in line with it.
- Height: 3 inches, bold block characters
- Spacing: Space or hyphen
- Location: Forward half of each side, for maximum visibility
- Validation decal: 4 inches toward the stern from the registration number and in line with it
Diagram is illustrative. Confirm exact positioning against the instructions issued with your Iowa registration.
Official source
Iowa Department of Natural Resources — Primary state agency source. Last verified August 22, 2026 (source check 2026-08-22).
Iowa DNR — BoatingRegistration 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.
Iowa rules in detail
Minimum character height
Iowa 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
Bold BLOCK characters, reading left to right. Script, italic and decorative treatments are not what this style describes.
Contrast requirement
Must contrast with background. 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
Space or hyphen. Example: IA 3717 ZW. Running the groups together with no separation does not match the stated format.
Placement on the hull
Forward half of each side, for maximum visibility. No other numbers on either side of the bow.
Validation decal placement
4 inches toward the stern from the registration number and in line with it. The validation or expiration decal is issued by Iowa Department of Natural Resources — RegistrationDecals.com supplies the registration-number lettering only.
Common mistakes
- Ordering the number without the IA prefix or the suffix letters.
- 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 bold BLOCK characters.
- Losing the required separation between the groups — space or hyphen.
- Placing the state validation decal somewhere other than the position Iowa describes: 4 inches toward the stern from the registration number and in line with it.
Frequently asked questions
What does a Iowa boat registration number look like?
Iowa numbers follow the pattern IA 3717 ZW, using the IA prefix, a numeral group, and suffix letters.
How tall do Iowa boat registration numbers have to be?
3 inches, measured on the character itself, in bold BLOCK characters.
What lettering style does Iowa require?
Bold BLOCK characters, reading left to right, and must contrast with background.
How much space goes between the letters and numbers in Iowa?
Space or hyphen. Example: IA 3717 ZW.
Where do the numbers go on the boat in Iowa?
Forward half of each side, for maximum visibility. No other numbers on either side of the bow.
Where does the Iowa validation decal go?
4 inches toward the stern from the registration number and in line with it. The decal itself is issued by Iowa Department of Natural Resources; we supply the registration-number lettering.
Who regulates boat registration numbers in Iowa?
Iowa Department of Natural Resources. Confirm the current instructions issued with your registration before applying anything to your hull. Last regulatory review: August 22, 2026.
Can I order Iowa boat registration numbers online?
Yes. Enter your assigned IA 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.
Do I need two sets of Iowa registration numbers?
You need the number displayed on both sides of the vessel — forward half of each side, for maximum visibility — so every order ships as a matched port-and-starboard pair.
Related guides
Ready to design your IA numbers?
Our designer starts with plain block characters and proper group spacing, so you can see exactly how IA 3717 ZW will read on your hull before you order.
Source: Iowa Department of Natural Resources · 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.