Who Should Wear a Life Jacket?
Anyone participating in any boating, paddling or towed water sport regardless of swimming ability.
Inexperienced or non-swimmers in pool or open water situations when other layers of protection are limited.
Preschool children—those about 5 years and younger—who are not protected by touch supervision either in or near the water. Touch supervision means being within an arm’s reach of the child(ren) at all times.
In addition, it is recommended that everyone who is in or around open water wear a life jacket as an extra layer of protection, especially outside of a lifeguarded area
Original source can be found here.