CS One Co., LTD.

CS One Co., Ltd., a Japanese limited liability company based in Yokohama, provides facility maintenance, repair, and infrastructure support services to the U.S. Department of Defense at military installations throughout Japan as a prime contractor on an exclusively full-and-open (non-set-aside) basis. The vendor competes openly for federal work with no SBA designations and serves a heavily concentrated customer base dominated by Navy operations in the Asia-Pacific region.

The company's core capability set centers on fire protection systems maintenance, intrusion detection system (IDS) repair and modernization, electrical infrastructure support, and base operations services at strategically important military facilities including Naval Air Facility Atsugi, Yokosuka Naval Base, and the New Sanno facility in Tokyo. Representative work includes a $1.3 million recurring project management and inspection services order for fire protection and IDS work at Yokosuka Naval Base (fiscal 2023), a $1.1 million recurring base operations support contract modification at New Sanno for fire protection, IDS, electrical, and communication systems (fiscal 2025), a $847 thousand delivery order for New Sanno base operations support issued in December 2025, and routine service orders ranging from $1,929 to $596 thousand covering sprinkler system repairs, fire alarm control panel replacements, and smoke detector installations across Navy installations in Japan.

Customer concentration is extreme: the Department of the Navy Installations Command accounts for 220 of the vendor's 291 total prime awards (75% by count) and $105.9 million of the combined potential value, representing 84% of the dollars. The Department of the Navy Naval Facilities Engineering Command, Department of Defense Education Activity, Defense Logistics Agency Distribution, and the Navy Bureau of Medicine and Surgery round out the top five agencies, collectively representing 9% of remaining awards and $11.3 million in potential value. The top-customer rankings by award count and by dollar value align closely, with Navy Installations Command dominating both metrics.

CS One holds five principal Indefinite Delivery Contracts (IDCs) serving as the parent vehicles for its delivery orders. The largest by task-order volume is IDC N4008415D0410 with 66 task orders and $6 million combined potential value, followed by N4008420D0101 with 62 task orders and $11.8 million, N4008410D0408 with 43 task orders and $5.2 million, N4008420D8701 with 35 task orders and $4.5 million, and N4008415D8701 with 20 task orders and $3.9 million. More recently, the vendor was awarded two single-award IDCs: a $17.8 million contract (N4008425D0410) effective April 2025 through April 2033 for maintenance of fire protection systems, IDS, and electrical infrastructure at Naval Air Facility Atsugi, and a $7.6 million contract (N4008425D0405) effective November 2024 through December 2029 for base operations support at New Sanno covering fire protection, IDS, CCTV, electrical, and communications systems.

Activity has grown year over year—19 awards in 2022 and 2023, 12 in 2024, 28 in 2025, and 4 in the first quarter of 2026. Thirteen awards carrying a combined potential value of $2.5 million reach ultimate completion within the next twenty-four months and face recompete exposure. The vendor's work portfolio spans electrical contracting and installation (136 awards), facilities support services (88 awards), commercial and industrial machinery repair (36 awards), and support for fire protection housekeeping (19 awards), reflecting its positioning as a specialized base operations and critical-infrastructure maintenance provider rather than a general contractor.

CS One operates exclusively as a prime contractor—all 291 awards in the source are prime awards with zero subcontract activity. The company has maintained continuous System for Award Management registration since 2005 and competes for all work through open and unrestricted competition, indicating establishment as a trusted partner for Department of Defense facility operations in Japan with no need for small-business set-aside vehicles.