The purpose of this research is to discover adequate and environmental outdoor playground design criteria based on the collected opinions of experts. Taking the case of South Korea into account, this research focuses on the development of a new outdoor playground design criteria that could offset the limited motor activities and environmental use which has been restricted by the current regulations. In particular, this research approaches the issue from the perspective of children’s fundamental movement skills and the development of their perceptual-motor abilities. The research conducted three rounds of a Delphi survey and held a consensus of experts in child development, child physical education, and playground designs. The research achieved results defining 9 categories and 23 items within the categories of design criteria for outdoor playgrounds. Significantly, the discussions were not limited to children’s holistic development—from motor and physical development to attaining mental, social, and cognitive skills—but also included discussions of children’s dynamic interaction with the surrounding nature and environment, especially in challenge making and risk taking.