A sponson attachment for an airboat allows the airboat to increase its safety and stability very quickly. A method for attaching a sponson to an airboat hull includes attaching first and second flexible tethers to a side of the sponson. The method also includes removably securing the first flexible tether to an exterior of the airboat hull adjacent a gunnel, and removably securing the second flexible tether below the first flexible tether on the exterior of the hull.