When boating season arrives. With that comes the questions of decals for boats. Yes, you can put decals on boats. Though decals will only be warrantied if they are above the waterline on the boat. Decals below the waterline can be done, though dependant on how often they are used, speeds you travel, and a few more variables, they may last only a few uses, or they could last a year. Its just an unknown. With that being said, most companies will recommend against it to save you your money, though if it is something you really want to take a chance on, you can still get it done.