Abstract: An adjustable stairway system provides access between a first elevation level and a second elevation level. The system includes a pair of expandable and retractable scissor stringers and multiple spaced apart treads joining the pair of stringers. The system further includes a first mounting assembly structured to allow a top portion of the stairway to be relatively permanently secured to a landing or other man-made structure, and second, different mounting assembly that allows a bottom portion of the stairway to be removably secured to natural terrain such as a beach. The system sometimes includes a control assembly to assist in expanding or retracting of the stairway.