A stability device that increases foot security on the footbed of a shoe, provides lateral or medial stability, shock dampening, and optimizes flexibility. The stability device includes a resilient bladder insert having a horizontal sole portion underneath a wearer's foot, and a foot portion positioned along a lateral or medial side edge of a wearer's foot. The sole portion and the foot portion are in fluid communication. The stability device can be generally L-shaped to cradle a portion of the foot. The stability device can also include a plurality of finger-shaped elements that encircle the top of the foot and expand down onto the foot due to an increase in fluid pressure therein.