The “state of principal use” – or the state where it’s likely to be used most throughout the year – plays a crucial role here.
Registration laws generally only apply to state residents. If you’re required to register your kayak, you should do so in its state of primary use. However, most states will also have a reciprocity law that allows visitations without the paperwork and fees:
Out-of-state paddlers are often given a window of up to 90 days when the kayak can be used without registering. After that, the state you’re visiting becomes its “state of principal use,” meaning you’ll have to register your kayak accordingly.