Mobilization of mission trips: The case of northbound Catholics in Hong Kong

China’s ‘reform and opening-up’ in 1978 offered new but uncertain opportunities for people in Hong Kong, then a British colony, to travel northward to mainland China. Many were to contribute to the country’s economic revival. Understudied was a group of Catholics who capitalized on the new situation to reconnect the Church on the mainland with the universal Catholic Church. What motivated these ‘northbound Catholics’ to repeatedly embark on such short-term mission trips? This article adopts the additive model of demand and supply developed by the social movement scholar Bert Klandermans to examine why and how these religious practitioners were recruited. Based on in-depth interviews and archival research, this article shows that identity, ideology, and instrumentality on both the demand and supply sides were essential during the process. The findings suggest that the study of religious actions could benefit from social movement studies.