JMSDF Yokosuka Naval Base (横須賀基地)

JMSDF Yokosuka Naval Base is the Japan Maritime Self-Defense Force installation at Yokosuka, Kanagawa Prefecture, in the Kantō region on the western shore of Tokyo Bay. It is not a single enclosed compound but a group of ports and shore facilities distributed across several districts of the city — Funakoshi, Yoshikura, Nagaura, Arai, Kusugaura, Taura and Takeyama — and it adjoins United States Fleet Activities Yokosuka. The name is a common usage rather than an official designation; the installation is administered by the Yokosuka District Force.

The Funakoshi district holds the highest JMSDF operational headquarters afloat: the Self Defense Fleet Command, together with the Fleet Escort Force, Fleet Submarine Command, Mine Warfare Force Headquarters, Fleet Research and Development Command, Fleet Intelligence Command and the Oceanography ASW Support Command, alongside the Yokosuka District Force, the 41st Mine Warfare Force and base service and medical units. Surface combatants are berthed at Yoshikura, which hosts the 1st Escort Flotilla Command with the 1st Escort Squadron, and the 2nd Escort Flotilla with the 6th Escort Squadron, plus the Yokosuka District General Manager, Communications Command elements, the Yokosuka System Communication Corps and the district police. Submarine forces are concentrated at Kusugaura, where the Fleet Submarine Command maintains the 2nd Submarine Squadron alongside the Oceanographic Command's anti-submarine support group and anti-submarine data corps. Arai holds the Maritime Training Guidance Group Command, the Submarine Education and Training Corps and the Yokosuka Guard. Training and logistics are centred on Taura, seat of the 2nd Technical School, the MSDF Supply Headquarters and Ship Supply Office; the Yokosuka Education Corps and Music Corps are at Takeyama.

Repair and logistic support is provided by the Yokosuka Repair and Supply Station, present at Yoshikura, Kusugaura and Taura, and by the Yokosuka Ammunition Maintenance Supply Station at Arai, formed from the former torpedo and guided-munitions maintenance stations. Yoshikura Pier was completed in 1980 and the Hemi Dock in 2010. Fuel is held at the Kurihama oil storage station. The Diving Medical Experiment Corps at Taura operates a pressure chamber facility simulating depths to 450 m.

The base originated on 26 April 1952 with the Coastal Safety Force's Yokosuka Regional Supervision Department, established on the site of the former Suirai Naval Academy at Tauraminatochō. Reorganisation followed the creation of the National Safety Agency on 1 August 1952, and on 19 October 1953 the Yokosuka District Force moved from Taura to Nishihemichō.