A safety liner for retaining liquids in a confined volume wherein liquid impervious side and bottom walls are positionable into the liquid retaining position by reason of flotation means or buoyant portions maintaining the side walls in the liquid confining relationship to prevent liquid spills and runoffs. An exemplary use of the safety liner is as a safety flotation liner for use in waterbed structures wherein inadvertent rupture of the water mattress will prevent water spills by reason of use of the flotation liner, which will permit emptying of the escaped water in a safe and efficacious manner without damage to the surroundings.