Abstract: An inflatable buoyancy belt is disclosed comprised of a segment of expandable tubing closed at either end with flattened plugs, carrying fittings enabling adjustable securement of a nonstretchable belt, the tubing segment and connected belt each of a length to extend approximately half way around a wearer's trunk. A gas cartridge holder-inflator fitting is incorporated into one of the end plugs, the gas cartridge releasing a volume of gas only partially inflating the tubing segment, causing a localized bubble to be formed, acting as a buoyancy chamber confined to one side of the wearer's body. The lengthening of the tubing segment at inflation offsets the tightening effect of the bubble to insure a sufficiently loose fit to the wearer so as to allow ready adjustment of the position of the bubble to the wearer's upper trunk.