The emergence of colonialism and the Cold War’s relocation of geopolitics had a profound effect not only on high politics but also on the populace on the ground. Vietnamese nationalists and communists utilised Thailand as a major geographic conduit in their anti-French colonialism and anti-American operations. During the Cold War, temples and churches became the political refuge for Overseas Vietnamese (Việt Kiều) and the arena of conflict between the various groups of supporters, namely Hanoi and Saigon supporters. As Thai authorities monitored these Vietnamese activities, religious space became a refuge for overseas Vietnamese who required protection from the Thai government. From the 1950s to the 1970s, the Cold War encompassed more than the proxy conflict between bipolar political ideologies. This was instead a fierce conflict between people on the ground. The Thai government was concerned about the Overseas Vietnamese in northeastern Thailand, who were predominantly perceived as communists and had ties to the anti-colonial struggle. Using Vietnamese and Thai archival sources as well as oral history, this chapter examines the history of the Cold War from below through the transnational lives of the Overseas Vietnamese, particularly the use of religious space as a sphere of the Overseas Vietnamese’ political mobilities.