In parallel to the growing impacts of various new technologies such as artificial intelligence on societies, the environment, ecosystems, and human lives, financial technologies (FinTech) are playing an increasingly important role in the organization of financial systems and economies worldwide. To verify this claim, the present article takes a closer look at the role of the regulation of FinTech in the context of the regional cooperation in the Greater Bay Area (GBA). The GBA currently comprises the two Special Administrative Regions of Hong Kong and Macao and the nine municipalities in the Guangdong Province of the People's Republic of China (PRC), which together form one of the world's most dynamic and innovative regions. Based on each of the GBA members' unique legal systems, united under the principle of 'one country, two systems', the GBA can be regarded as a fertile testing ground, 'legal laboratory', or 'regulatory sandbox' for the regulation of FinTech worldwide. For this purpose, the article first introduces the existing legal framework, fleshing out the contours of the GBA. Second, it briefly outlines the current scope of FinTech and provides examples of its use in the GBA. The main focus of the article then shifts from FinTech to the regulatory challenges posed by FinTech in the GBA, and the article discusses how these may best be addressed by, for instance, relying on regulatory technology (RegTech) and so-called 'regulatory sandboxes'. The article concludes by arguing for both an early and a comprehensive discussion about the expected benefits and the potential risks of the rapid implementation and use of FinTech in the GBA and the world at large.