Southern Chinese lion dance (nanshi) in Bangkok moves between temple ritual, community representation, school training, and judged competition, yet these domains are rarely analyzed together. Focusing on recent institutional transformation within one influential Teochew-centred ecology, this article examines how ritual governance, competition, and heritage-making have become mutually reinforcing. The study combines multi-sited historical ethnography in Bangkok and Guangdong (2022-2023) with documentary traces from the 2000s-2020s, including temple and association commemorative publications, municipal school records, Thai cultural and competition reporting, heritage registers, and transnational rule texts. It finds that huiguan and temples stabilize calendars, patronage, and authority, while judged competition introduces auditable norms of time, safety, team composition, and difficulty. These regimes do not simply displace ritual; they reorganize it. Certificates, trophies, lion heads, photographs, and anniversary volumes turn performance credentials into community archives that narrate continuity, merit, and public legitimacy. Rather than a linear shift from ritual to sport, the Bangkok case shows how codification, temple-linked patronage, and heritage discourse jointly reshape a diasporic ritual practice.