The answer is no you will not have to pay sales tax on it. You will need a substantial bit of proof of residency including a drivers license. Just out of curiosity why buy a boat in Seattle? Gettin' a good deal or what?
Oregonian's BEWARE! If you ever plan on moving to Washington and bought your boat in Oregon or any state that does not have sales tax you will have to pay it when you move here regardless of how old your boat is! I got married in August and moved to Camas from Lake Oswego. I have a two year old North River and will have to pay $1500 in WA Use Tax!! :shocked:
Yes you read that right a USE TAX! Here is the kicker, if you bought your boat in another state that does have sales tax, you don't have to pay the use tax? So its not a use tax because anyone who boats in WA uses the water. It is a "were gonna' get your money no matter what" tax. You cannot register your boat without paying the tax! So now I have my beautiful boat that will sit until who know when and we can afford to pay the tax.

The tax is calculated based on the fair market value of your boat and the SALES tax rate for your area of WA. No matter how you look at it I am paying sales tax on my two year old boat. :whazzup: