Micronesia was governed by Spain, then Germany, then Japan, then the United States within a single lifetime, and each administration brought or restricted religion differently.
Catholic missions came with Spanish rule and remain strongest in the Marianas and parts of the Carolines. American Protestant missionaries worked in the Marshalls and eastern Carolines from the 1850s, and German and Japanese administrations tolerated, regulated or suppressed missions according to their own interests. Japanese rule brought Shinto shrines for settler communities and, in its later phase, pressure on Christian churches; the Pacific War then made several islands battlefields, and the Marshall Islands were used for nuclear testing afterwards, displacing whole communities from atolls they understood as ancestral.
Modekngei, which arose in Palau in the early twentieth century, is the region's most significant indigenous new religion. It combined existing Palauan practice with Christian elements, was suppressed by the Japanese administration, whose officials imprisoned its leaders, and survived to become a recognised body with its own school. It is usually described as an assertion of Palauan religious autonomy against successive foreign authorities.
Christianity is now the majority religion across Micronesia, and older practice persists in specific domains: the treatment of particular sites, the handling of death, the knowledge held by navigators and healers, and the customary law that governs land.