JMSDF Ōminato Naval Base (大湊基地)

Ōminato Naval Base is a Japan Maritime Self-Defense Force installation on Mutsu Bay at Mutsu, Aomori Prefecture, at the northern end of Honshū. It combines port facilities with a military aerodrome (ICAO: RJSO) and is the seat of the Ōminato District Force, the JMSDF regional command responsible for the waters off northern Honshū, including the approaches to the Tsugaru Strait.

The base headquarters the Ōminato District Force and hosts its subordinate elements: the Ōminato Communications Command, the Ōminato Coastal Safety Force, the Ōminato Base Operations Corps, the Ōminato District Police, the Ōminato Music Corps and medical detachments. Escort vessels of the Fleet Escort Force are homeported at Ōminato, with an escort division berthed at the base. Units of the Self Defense Fleet and the Fleet Air Force also use the installation.

The co-located Ōminato Air Base falls under the 25th Air Group, itself subordinate to the 21st Air Group of the Fleet Air Force. Its flying element is the 251st Squadron (call sign BATTLEAX), equipped with Sikorsky SH-60J and SH-60K helicopters configured for anti-submarine warfare and assigned to patrols of the Tsugaru Strait. Supporting formations include the 251st Maintenance Supply Corps and the Ōminato Air Base Corps. A detachment of Sikorsky UH-60 utility helicopters from the 73rd Air Group at Tateyama Air Base operated from Ōminato until 2 April 2018.

Shore support includes the Ōminato Repair Supply Station and the Ōminato Ammunition Maintenance Supply Station. The Self-Defense Forces Ōminato Hospital, opened on 9 August 1960, was reduced to a clinic in late March 2021 following the expansion of the Self-Defense Forces Yokosuka Hospital.

The Ōminato District Force was formed on 16 September 1953 under the Coastal Safety Force of the National Safety Agency, the predecessor of the JMSDF, and the Ōminato Garrison was established on 20 January 1954 and abolished on 15 August 1962. The Ōminato Air Corps was raised on 16 May 1956 under the District Force; on 26 March 2008 it was transferred to the 21st Air Group and reorganised as the 25th Air Group.