Yokosuka is a city in Kanagawa Prefecture, Japan.
As of October 2017, the city has a population of 409,478, and a population density of 4,066 inhabitants per square kilometre. The total area is 100.7 km². Yokosuka is the 11th most populous city in the Greater Tokyo Area, and the 12th in the Kantō region.
The city is host to United States Fleet Activities Yokosuka.