Yaizu is a city located in central Shizuoka Prefecture, Japan. As of 1 May 2019, the city had an estimated population of 139,578 in 57,593 households, and a population density of 2000 persons per km2. The total area of the city was 70.31 square kilometres (27.15 sq mi). Yaizu is a noted port for commercial fishing.

Shizuoka Prefecture is a prefecture of Japan located in the Chūbu region of Honshu. As of September 2023, Shizuoka Prefecture has a population of 3,555,818 and has a geographic area of 7,777.42 km2 (3,002.88 sq mi). Shizuoka Prefecture borders Kanagawa Prefecture to the east, Yamanashi Prefecture to the northeast, Nagano Prefecture to the north, and Aichi Prefecture to the west.