A life jacket is a personal flotation device designed to keep the wearer's head above water even if the wearer loses consciousness. Life jackets provide greater buoyancy than buoyancy aids and are designed for severe conditions, whereas buoyancy aids are designed to aid people who are capable of swimming.
The design of a life jacket places the foam core around the neck and shoulders, which can restrict movement. In a buoyancy aid, the foam core is situated so that the wearer does not lose freedom of movement. Buoyancy aids are popular with canoeists, who need the extra range of movement.