Mississippi Code Title 59. Ports, Harbors, Landings and Watercraft § 59-21-81

(1) Every vessel shall have on board a Coast Guard approved personal flotation device for each person aboard such vessel, and every person twelve (12) years or younger on board a motorboat, sailboat, or vessel which measures less than twenty-six (26) feet in length shall wear a type I, II, or III Coast Guard approved personal flotation device while such motorboat, sailboat, or vessel is underway. For the purpose of this section “underway” shall mean at all times except when a motorboat, sailboat, or vessel is anchored, moored, or aground. Every vessel shall have lights during the hours of darkness, which comply with all federal regulations applicable to vessels of its classification. Such vessel shall not be operated unless in a safe and seaworthy condition; the owner and operator shall employ such safety devices as may be necessary for the safe operation of such vessel, including an efficient natural or mechanical ventilating system when necessary for safe operation. In addition to the requirements imposed by this section, all vessels shall comply with all federal regulations applicable to vessels of such classification.

(2) For purposes of this subsection, “personal watercraft” means a vessel which uses an inboard motor powering a water jet pump and which is designed to be operated by a person sitting, standing or kneeling on the vessel, rather than the conventional manner of sitting or standing inside the vessel. A person shall not operate a personal watercraft unless each person on board or being towed behind is wearing a type I, type II or type III, personal flotation device approved by the United States Coast Guard.