Japan Marine United Corporation

Japan Marine United was formed on 1 January 2013 by merging Universal Shipbuilding with IHI Marine United, bringing two lineages of Japanese yard capacity under one roof. Ownership has since shifted. Imabari Shipbuilding holds 60 per cent, with JFE Holdings and IHI on 20 per cent each, and the two partners also operate the Nihon Shipyard design and marketing venture set up in 2021. Capital stands at 57.5 billion yen and the head office is in Minatomirai in Yokohama. Seven yards carry the work, at Ariake, Kure, Tsu, Maizuru, Isogo, Tsurumi and Innoshima, supported by two research centres. The company describes four business areas, Merchant Ship, Naval Ship and Marine, Offshore and Engineering, and Ship Lifecycle.

Naval construction is what makes JMU strategically significant. The Isogo yard in Yokohama built both Izumo class helicopter destroyers, JS Izumo commissioned in March 2015 and JS Kaga in March 2017, and is carrying out the modification work that lets them operate F-35B aircraft, reshaping the bow and reinforcing the flight deck against jet exhaust and vertical landing loads. The same yard delivered both Maya class Aegis destroyers, JS Maya in March 2020 and JS Haguro a year later, the first Japanese ships with Baseline 9C and hybrid electric drive. In September 2024 the Ministry of Defense contracted JMU for the second Aegis System Equipped Vessel at roughly 132.4 billion yen, a very large missile defence ship built around SPY-7, due for delivery in 2028 after the lead vessel from Mitsubishi Heavy Industries. Mine countermeasures are a quieter speciality, with the Awaji class of fibre-reinforced plastic minehunters, among the largest composite hulls afloat, launched steadily since 2015. The class runs to 690 tons standard displacement with a crew of about 50, and nine hulls are planned, JS Awaji commissioning in 2017, JS Hirado in 2018, JS Etajima in 2021 and JS Nomi in 2025, with JS Kerama launched in 2025 for delivery the year after. Naval repair and conversion work runs alongside new build. Isogo has handled repeated docking periods on Izumo since 2024 as the second phase of that conversion ran.

Commercial output is the volume business. JMU builds container ships, bulk carriers from Panamax through Capesize to very large ore carriers, VLCC, Suezmax and Aframax tankers, LNG and very large gas carriers, pure car carriers, ferries and cruise vessels, and offshore support ships. Offshore and Engineering applies the same steelwork to floating structures and gas processing facilities, with floating offshore wind foundations and carbon-neutral fuel propulsion as stated development priorities alongside autonomous navigation. Ship Lifecycle covers dry dock repair, equipment inspection, worldwide spare parts supply, marine equipment and mechatronics. For a defence buyer the summary is straightforward. JMU is a commercial shipbuilder first, with a naval order book concentrated on a handful of high-end Japanese surface combatants and mine warfare vessels, and no export track record in warships.