Regarding registration, vessels must be registered with the Local Tax Collector’s Office within 30 days following the purchase. A few exceptions to this rule apply, such as non-motorized boats under 16 feet in length and non-motorized canoes, kayaks, racing shells, and rowing sculls.
Boaters must display the vessel registration number on each side of the boat, forward of the transom, as high as possible above deck and visible from the water. It must be in block letters and figures at least 3 inches high and in a contrasting color, so it is clearly visible. The numbers must be separated from the letters by a hyphen or space equal to the width of a letter.
Any time your boat is in operation, your registration certificate must be aboard and available for inspection if you are stopped by law enforcement.
A boat registration decal is a sticker indicating that a vessel has been registered in Florida. It must be placed on the front of your boat—either before or after the number on the port side (left side) — within 6 inches of the registration numbers on that side. Your boat must be registered and display a valid decal at all times when operating in Florida waters.
If you have brought into Florida a boat that you own but is currently registered in another state, you may operate the vessel without registering that boat with the Florida DMV for no more than 90 consecutive days. But under no circumstances can you operate an out-of-state boat in Florida waters for more than 90 consecutive days without registering it with the Florida DMV.