Nagasaki's 2025 population is now estimated at 396,587. In 1950, the population of Nagasaki was 163,000. Nagasaki experienced a decrease of -3,407 residents over the past year, marking an annual decline of -0.85%.These population estimates and projections come from the latest revision of the UN World Urbanization Prospects. These estimates represent the Urban agglomeration of Nagasaki, which typically includes Nagasaki's population in addition to adjacent suburban areas.