Uki is a city in Kumamoto Prefecture, Japan. As of 1 September 2024, the city had an estimated population of 56,491 in 25302 households, an…Uki is a city in Kumamoto Prefecture, Japan. As of 1 September 2024, the city had an estimated population of 56,491 in 25302 households, and a population density of 300 persons per km². The total area of the city is 188.67 km².