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 hous…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. Yaizu is a noted port for commercial fishing.