JS Yoshii

History
Japan
Name	Yoshii
Namesake	Yoshii River
Builder	Mitsubishi Heavy Industries Nagasaki Shipyard
Cost	Approximately 46 to 47 billion yen
Laid down	3 July 2024
Launched	22 December 2025
Commissioned	Fiscal year 2026 (scheduled)
Identification	FFM-12
Status	Fitting out
General characteristics
Class & type	Mogami-class frigate
Displacement	3,900 t (3,800 long tons; 4,300 short tons) (standard) 5,500 t (5,400 long tons; 6,100 short tons) (full load)
Length	132.5 m (434 ft 9 in)
Beam	16.3 m (53 ft 6 in)
Draft	9 m (29 ft 6 in)
Propulsion	CODAG 1 × Rolls-Royce MT30 gas turbine 2 × MAN Diesel V28/33DD STC engine 2 × shafts
Speed	30 knots (56 km/h; 35 mph)
Boats & landing craft carried	2 × RHIB, UUV, USV
Crew	90-100
Sensors & processing systems	OPY-2 (X-band multi-purpose AESA radar) OAX-3(EO/IR) OQQ-25 (VDS + TASS) OQQ-11 (Mine-hunting sonar) OYQ-1 (Combat management system) OYX-1-29 (Console display system)
Electronic warfare & decoys	NOLQ-3E (Passive radar system + Electronic attack capability is integrated into the main radar antenna), Chaff dispenser
Armament	1 × 5 in (127 mm) Mk-45 Mod 4 naval gun 2 × missile canisters for a total of 8 Type 17 anti-ship missiles 1 × SeaRAM Type 12 torpedoes Simplified mine laying equipment 2 × Mk-41 VLS (16 cells total) Naval version of Type 03 Chū-SAM 2 × Remote weapon station
Aircraft carried	1 × SH-60K patrol helicopter

JS Yoshii (Japanese: よしい; Hull Number: FFM-12) is the 12th and last ship of the Mogami-class frigates of the Japan Maritime Self-Defense Force. She is named after the Yoshii River in the Okayama Prefecture, a name that had not been previously used by the Imperial Japanese Navy.^[1][2]

Construction and career

Yoshii was laid down in July 2024, at the same time as her sister ship Tatsuta.^[2] The ship was launched at Mitsubishi Heavy Industries' Nagasaki Shipyard on 22 December 2025, with Minister of Defense Shinjiro Koizumi attending the ceremony.^[1][2] The combined construction cost for both Yoshii and Tatsuta was approximately 116.6 billion yen. Yoshii is scheduled to be commissioned in the fiscal year 2026.^[1]

References

1. "海上自衛隊の新護衛艦　岡山県東部流れる吉井川由来「よしい」に　吉井川由来の艦艇名は初めて【岡山】" [The Japan Maritime Self-Defense Force's new escort ship will be named "Yoshii," a reference to the Yoshii River that flows through eastern Okayama Prefecture. This marks the first time a vessel has been named after the river.]. Yahoo! News Japan (in Japanese). 22 December 2025. Retrieved 22 December 2025.
2. "小泉進次郎防衛相も臨席！ 海自最新のステルス護衛艦「よしい」進水 史上初の艦名その由来は？" [The 12th Mogami-class ship is named after a river in Okayama Prefecture.]. Traffic News (in Japanese). 22 December 2025. Retrieved 22 December 2025.