This article examines how Anglo-American evangelicals in colonial Korea employed racialized understandings of the environment to justify a culture of recreation and health. In the metropole and periphery, missionary researchers studying climate, geography, and public health asserted a  science-based injunction to rest that was intended to maintain a population of evangelical workers. The production of this scientific research, external to the Japanese colonial state, allowed the missionary community to establish a rationale for collective segregation from the local populations they sought to save. In Korea, this dynamic is profiled through the history of a missionary resort at Sorai beach. Initially believed to have contributed to the suicide of an evangelical worker in 1895, within a few years the Sorai area rapidly transformed. In step with the broader culture of summer recreation that emerged in Korea during the 1910s and 1920s, the missionaries recast Sorai from a deleterious space into a site of strategic and devotional rest.