Under Washington state law, all seaplanes, including those registered in the United States or another country must purchase an Aquatic Invasive Species (AIS) prevention permit before placing or operating the seaplane in any waterbody in the state. In order to purchase a permit (click the "other" product category tab), the purchaser needs to provide the registration number. Each separate registered seaplane requires a permit.
Seaplanes are aircraft (including fixed wing and helicopters) that are able to land or take off from water. All civil aircraft are registered with a national aviation authority using procedures set by each country. The registration numbers are alphanumeric and displayed prominently on the aircraft.
How to locate the registration number
In the United States, the six-digit registration number is commonly referred to as an "N" number, because all aircraft registered in this country have a number starting with the letter N. After the letter N, there can be a five-digit number (N12345), four digits and one letter (N1234Z) or three digits followed by a two-letter code (N123AZ). The letter codes may not contain “I” or “O”, due to their similarities with the numerals 1 and 0. The registration number is not hyphenated.
In Canada, the airplane registration "number" starts with the letter "C" followed by a hyphen (-) and then a four-letter code.
A valid AIS prevention permit must be present and readily available for inspection by a fish and wildlife officer or ex officio fish and wildlife officer at the location where the seaplane is placed or operated.
Exempt seaplanes include:
Non-Washington State seaplanes that are not required to register or be licensed in another state or country;
Private or commercial seaplanes being transported over land by a commercial transporter (a permit is required by the commercial transporter only);
Military seaplanes owned by the U.S. government; and
Seaplanes clearly identified as being owned by any federal, tribal, state, or local government agency or other public entities, and used primarily for governmental purposes.