Sanya is the southernmost city on Hainan Island, and one of the four prefecture-level cities of Hainan Province in South China. According t…Sanya is the southernmost city on Hainan Island, and one of the four prefecture-level cities of Hainan Province in South China. According to the 2020 census, the total population of Sanya was 1,031,396 inhabitants, living in an area of 1,919.58 km². Nevertheless, its built-up area encompassing Haitang and Jiyang Districts was home to 801,020 inhabitants as of 2020.