Last month, Japanese media reported new scheduling details for a Japan Maritime Self-Defense Force (JMSDF) port facility planned for Amami Oshima, the largest island in the Amami archipelago located between Kyushu and Okinawa and considered a strategic site for maritime surveillance in the Pacific Ocean and logistical support to Japan’s southwestern Nansei Islands.
According to the regional news report,[1] the Japanese Ministry of Defense (JMOD) plans to seek approval by the end of fiscal year 2025 to reclaim land for the project from sections of Koniya Port in Setouchi Town, a locality situated in the southern part of Amami Oshima.
Redevelopment of the Sude District of Koniya Port into a JMSDF facility was approved by the Japanese Cabinet back in December 2024[2] and forms part of accelerated efforts to turn Amami Oshima into a logistics and surveillance hub.
The move comes amid increased Chinese military activity in recent years in the vicinity of Japan’s Nansei Island region near Taiwan, extending further northeast into the contiguous zone surrounding Amami Oshima itself.[3]
On Amami Oshima and in the vicinity of the repurposed JMSDF port facility, , a unit of the new SDF Maritime Transport Group tasked with the rapid transport of troops, vehicles and supplies to the southwest Nansei Islands is also scheduled to be deployed by fiscal 2026. JMOD is also proceeding with construction of new ammunition depots in the same area.
About the JMSDF Koniya Port Facility Development Project
Site assessments around Koniya Port on Amami Oshima first began in fiscal year 2023.
A Japanese Ministry of Defense (JMOD) suitability assessment[4] issued in December 2024 explained that Amami Oshima would be well suited both as a rear support base for operations to Japan’s southwest Nansei island region and as a monitoring and surveillance hub along the route between Kyushu’s southern Kagoshima region and Okinawa.
The ministry determined that Koniya Port’s Sude District in Setouchi Town would be a suitable location for the development of the JMSDF transport facility as the town already hosts a detachment from the JMSDF Amami Naval Base and a subcamp of the Japan Ground Self-Defense Force (JGSDF).
In fiscal 2024, JMOD detailed plans to develop wharves, fuel tanks, open storage areas, barracks, and warehouses that could serve to support the transport of supplies to Japan’s southwest Nansei region.
For fiscal 2025, the ministry subsequently allocated 200 million yen (approx. 1.3 million USD) for detailed design work for construction of the new JMSDF facility. This particular design phase is reported to run until the end of fiscal 2026.[5]
November 27’s regional news report[6] explains that, according to sources, JMOD’s land reclamation is planned on both sides of a prefecture-owned quay currently used for the transport of masonry and other materials. Approximately 0.7 hectares is to be reclaimed on the western side and about 2.9 hectares on the eastern side. The reclaimed areas will be used to construct quays necessary for the mooring of naval vessels.
The wharves to be constructed on the western side of the port facility are expected to measure 115 meters in length with a depth of 5 meters. Meanwhile, the wharves on the eastern side of the site will be longer and deeper, measuring approximately 240 meters in length with a depth of 11 meters.
Amami Oshima as a Naval Hub: Operational Significance
Local news indicates that the unit of the SDF Maritime Transport Group to be deployed to the JMSDF Amami Naval Base detachment in fiscal 2026 is to operate from the prospective port facility one transport boat measuring 35 x 8 meters.[7]
This relatively small boat likely refers to one of four “Maneuver Support Vessels” (機動舟艇). These fast landing craft are expected to form the core of the Group and are designed to offload high-mobility ground vehicles directly onto the shore of remote Nansei islands, many of which lack port facilities
The first of the four Maneuver Support Vessels is scheduled to enter service from fiscal year 2026,[8] indicating that the Amami detachment could be the first unit to receive them.
Redevelopment of Amami Oshima’s Koniya Port coincides with JMOD efforts to boost naval infrastructure across other parts of Japan to support JSDF operations to the country’s southwestern islands.
In Hiroshima’s Kure District, JMOD is engaged in discussions with local government authorities to turn a former Nippon Steel site into a “Multi-functional Composite Defense Base” that will feature port facilities.
Although located in Honshu, the Kure multi-functional base is similar to Amami Oshima’s Koniya Port in that it is expected to provide access to the Pacific Ocean and Japan’s southwestern Nansei Islands (along with the Sea of Japan).[9] Nearby is also the main force of the Maritime Transport Group located at the nearby Kure Naval Base.
Situated between Kure and Amami Oshima, the uninhabited island of Mageshima is also being developed by JMOD as a new air base intended to reinforce Japan’s defenses in the southwestern islands.
Linking the Amami Oshima JMSDF Port Facility with Local Business Interests
JMOD has explained to local organizations in Setouchi Town that it aims to fully consider the impact of the JMSDF port project on the surrounding area. As part of this effort, the ministry stated in December 2024 that it was planning to consult with Setouchi Town officials.[10]
Setouchi Town’s Mayor Naruhito Kamada welcomed the move to establish the port facility, and expressed hope that funding for the development would be approved by the central government.[11]
At the same time, the Mayor explained that the local authority would also strive to ensure that the Town’s views were reflected in JMOD’s development of the facilities.
In June of this year, Mayor Kamada and members of the “Setouchi Town JSDF Base Measures Promotion Council” met with officials from JMOD to discuss the latest on the project.[12]
Drawing on input from the Construction Industry Association, the Chamber of Commerce, and other local organizations, the Mayor and Promotion Council formally requested that local businesses be given priority in the awarding of contracts.
One of the most noteworthy requests was for the priority use of local construction companies and related firms in work related to “surveillance vessels.”
The request also called for the participation of local businesses in port facility construction joint ventures, as well as the development of dock and maintenance facilities that could be used by both JMSDF vessels and local commercial vessels.
A similar linkage between JMOD-initiated redevelopment and advocacy of local business interests by regional governments can also be observed in the aforementioned Kure multi-functional composite defense base, in response to which the Hiroshima Prefectural Government has sought shipbuilding, aviation fuel production and drone industry investment.
Conclusions
The latest news that JMOD is planning to move forward with reclaiming the land needed for its JMSDF port facility on the strategically located Amami Ōshima by the end of this fiscal year demonstrates Tokyo’s recognition of the urgent need to accelerate surveillance capabilities and logistics infrastructure for the southern Nansei Islands region amid an increase of Chinese military activities in the region.
As Tokyo bolsters JSDF facilities across various parts of the country, regional government authorities are responding by promoting business interests that are relevant to the defense sector. The focus tends to be on both reinforcing local industry, including shipbuilding and construction, and incentivizing the introduction of new sectors, including autonomous systems.
Note:
**1 USD = 156 JPY
[1] Minami-Nippon Shimbun, “奄美大島・瀬戸内町に自衛隊の港湾施設を整備 2025年度内に埋め立て申請へ 近くの奄美基地分遣隊には26年度に新部隊 防衛省” [The Ministry of Defense plans to develop port facilities for the Japan Self-Defense Forces in Setouchi Town on Amami Oshima, with land reclamation application due by the end of fiscal 2025. Nearby Amami Base Detachment to welcome new troops in fiscal 2026], November 27, 2025, https://373news.com/news/local/detail/224674/.
[2] Setouchi Town, “海上自衛隊奄美大島地区（古仁屋港）に係る施設整備について” [Facility Development Related to the Japan Maritime Self-Defense Force Amami Oshima Area (Koniya Port)], Updated December 27, 2024, https://www.town.setouchi.lg.jp/kikikanri/kaijojieitai-shisetsuseibi.html.
[3] For more information on Japan’s observation of these recent Chinese military activities, see: JMOD, “Defense of Japan 2025” p.70, https://www.mod.go.jp/j/press/wp/wp2025/pdf/DOJ2025_EN_Full.pdf.
[4] JMOD, “瀬戸内町古仁屋港（須手地区）における港湾施設整備の適地判断について” [Regarding the Suitability Assessment for Port Facility Development at Koniya Port (Sude District), Setouchi Town], December 2024, https://www.town.setouchi.lg.jp/kikikanri/documents/tekichihandan.pdf.
[5] JMOD, “令和7年度予算案における海上自衛隊奄美大島地区（古仁屋港）に係る施設整備について” [Facility development related to the Japan Maritime Self-Defense Force’s Amami Oshima area (Koniya Port) under the fiscal year 2025 draft budget], December, 2024, ; Amami Shimbun, “鹿児島県瀬戸内町古仁屋港須手地区の自衛隊海上輸送施設 今年度から実施設計着手、防衛省に住民説明会要請” [The Japan Self-Defense Forces’ maritime transport facility in the Sude District of Koniya Port in Setouchi Town, Kagoshima Prefecture, will begin detailed design work this fiscal year, and the Ministry of Defense has been requested to hold a public briefing session.], December 10, 2025, https://amamishimbun.co.jp/2025/12/10/59596/.
[6] Minami-Nippon Shimbun, “奄美大島・瀬戸内町に自衛隊の港湾施設を整備 2025年度内に埋め立て申請へ 近くの奄美基地分遣隊には26年度に新部隊 防衛省” [The Ministry of Defense plans to develop port facilities for the Japan Self-Defense Forces in Setouchi Town on Amami Oshima, with land reclamation application due by the end of fiscal 2025. Nearby Amami Base Detachment to welcome new troops in fiscal 2026], November 27, 2025, https://373news.com/news/local/detail/224674/
[7] Ibid.
[8] JMOD, “Progress and Budget in Fundamental Reinforcement of Defense Capabilities – Overview of FY2025 Budget”, p.9, https://www.mod.go.jp/en/d_act/d_budget/pdf/fy2025_20250411a.pdf.
[9] JMOD, “防衛省による多機能な複合防衛拠点の整備に係るゾーニングについて” [Zoning for the development of a multi-functional composite defense base by the Ministry of Defense], March 2025, Slide 1, https://www.city.kure.lg.jp/uploaded/attachment/101657.pdf.
[10] JMOD, “瀬戸内町古仁屋港（須手地区）における港湾施設整備の適地判断について” [Regarding the Suitability Assessment for Port Facility Development at Koniya Port (Sude District), Setouchi Town], December 2024, https://www.town.setouchi.lg.jp/kikikanri/documents/tekichihandan.pdf.
[11] Naruhito Kamada, “自衛隊港湾施設、調査結果を受けて” [Regarding survey results for the JSDF port facilities], December 27, 2024, https://www.town.setouchi.lg.jp/kikikanri/documents/chocho-comment.pdf.
[12] Setouchi Town, “海上自衛隊港湾施設の早期完成と安全徹底や地元優先発注要望” [Request for Early Completion of JMSDF Port Facilities, Strict Safety Measures, and Priority Contracting for Local Businesses], Updated June 30, 2025, https://www.town.setouchi.lg.jp/kikikanri/kaijojieitaikowanshisetsuyobo.html.
This article was originally posted on NSBT Japan, the first defense and security industry network in Japan. The publication provides the latest information on security business trends both within Japan and overseas. Asian Military Review began exchanging articles with NSBT Japan in April 2024.
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