Okay, you got a SUP (Stand Up Paddleboard).  Did you know that per Coast Guard rules, if it is not operated within a surfing, swimming, or bathing area, it is considered a "VESSEL"?  Guess what, that means it is regulated like a vessel, and:

You are required to carry a PFD (if 13 or over) or WEAR IT (if under 13).
ALSO a whistle or other sound device is required.
AND, if after sunset, a flashlight is required.