Berry, A.; Fahey, S., and Meyers, N., 2013. Changing of the guard: adaptation options that maintain ecologically resilient sandy beach ecosystems.Sandy beach ecosystems adapt to sea-level rise by retreating landward. Retreat enables a sandy beach ecosystem to adapt while maintaining structure and function over various spatial and temporal scales. However, adaptation options, such as engineered barriers to shoreline retreat, reduce adaptive capacity and, therefore, ecological resilience to sea-level rise. Species richness and diversity becomes threatened when sandy beaches are squeezed between “fortifications” and increasing sea levels. Unidimensional management gives precedence to the protection of coastal investments at the expense of ecological resilience. This article provides a critical assessment of adaptation options to identify those capable of maintaining the ecological resilience of sandy beach ecosystems to sea-level rise. Hard- and soft-engineered options impede sand transport and storage systems and prevent retreat from advancing seas. In contrast, ecosystem conservation and setbacks enable coastal processes to continue and thereby maintain ecological resilience to sea-level rise. Managing sandy beach ecosystems from multidimensional perspectives allows coastal managers to better understand the consequences of implementing adaptation options. However, political, economic, and social necessity often dictates coastal managers employ unidimensional adaptation options to achieve quick results. This article proposes a four-dimensional lens through which sandy beach ecosystems can be viewed and managed. Longitudinal, transverse, vertical, and temporal dimensions characterise the function and structure of sandy beach ecosystems. A staged approach to adaptive management that takes a long-term view and considers a range of adaptation options tailored to achieve ecologically resilient sandy beach ecosystems is discussed.