The growing role of local governments and municipalities in international relations has become a significant trend that has shaped new dynamics in global affairs. By analysing Guangdong's subnational diplomacy and Guangzhou city's diplomacy activities, this article aims to investigate whether, and to what extent, Chinese provinces, autonomous regions and municipalities possess the freedom to act independently in planning, organising and managing their internationalisation processes. The article also debates the growing role of centralisation inside China and its impact on shaping local governments international activities. Using the case study of Guangdong and Guangzhou, the author examines the following questions: How do both provincial and local governments conduct their activities under China's foreign policy framework? How does the Belt and Road Initiative (BRI) impact the foreign activities of Guangdong and Guangzhou? Does China's central government attempt to make the division of labour among different provincial and city governments and how do both perceive themselves under the BRI "umbrella"? Through the analysis of the city, bilateral and multilateral activities and interviews conducted in Guangzhou and Guangdong Foreign Affairs Offices as well as with diplomatic personnel of the foreign countries, the author explores the dual-usage of city diplomacy in China's foreign policy from both economic and local development-oriented goals to its strategic role in regional and global affairs.