According to the Massachusetts Environmental Police: All SUP users on coastalwaters, when not in a bathing, swimming, or surf zone, are required by law to have a Type I, II, or III personal floatation device (PFD) aboard.  All SUP users on inland lakes or rivers, when not in a bathing or swimming area, are required by law to have a Type I, II, or III personal floatation device (PFD) aboard.    So, yes, whenever you’re out on your paddleboard, you need to have PFD at least on board with you, even if you’re not wearing it.