FLEET ACTIVITIES SASEBO

OVERVIEW

Fleet Activities Sasebo — formally Commander, Fleet Activities Sasebo (CFAS) — is the United States Navy's forward amphibious homeport, located on the northwest coast of Kyushu in Nagasaki Prefecture, Japan. It is the second-largest U.S. Navy installation in Japan after Yokosuka, and the closest U.S. naval base to the Korean peninsula, the Tsushima Strait, and the East China Sea.

Sasebo is the homeport of the U.S. 7th Fleet's forward-deployed Amphibious Squadron 11 and the only America-class amphibious assault ship permanently stationed overseas — currently USS America (LHA-6) — along with its supporting amphibious dock landing ships and an embarked Marine Expeditionary Unit. The base also hosts Mine Countermeasures Squadron 7, operating Avenger-class minesweepers in one of the few forward-deployed U.S. mine warfare missions worldwide. The combined Sasebo-based amphibious force is the U.S. Navy's principal forcible-entry capability west of Hawaii.

Approximately 7,500 U.S. military, civilian, and family members live and work at CFAS, integrated with the city of Sasebo and operating alongside the Japan Maritime Self-Defense Force's Sasebo District Headquarters at the same harbor. The base is built atop and around the original Imperial Japanese Navy's Sasebo Naval District, founded in 1889, and several of its piers, dry docks, and tunnels date to the late nineteenth and early twentieth centuries.

KEY FACTS

• Forward-Deployed Amphibious ForceHomeport of the only forward-deployed U.S. amphibious assault ship and amphibious ready group
• Strategic PositionNorthwest Kyushu — closest U.S. Navy base to the Korean peninsula and the East China Sea
• Imperial HeritageBuilt atop the Imperial Japanese Navy's Sasebo Naval District, founded 1889
• Joint OperationsOperates alongside Japan Maritime Self-Defense Force's Sasebo District Headquarters
• Mine Warfare HubHome of forward-deployed Avenger-class mine countermeasures ships of CMRON 7

HISTORY

Sasebo's emergence as a naval base began in 1889, when the Imperial Japanese Navy designated the deepwater inlet on Kyushu's northwest coast as one of its four principal naval districts (chinjufu), alongside Yokosuka, Kure, and Maizuru. Throughout the late 19th and early 20th centuries, Sasebo grew into a major fleet anchorage, shipyard, and naval gunnery and torpedo training base. The IJN's principal Korean Strait operating force was based at Sasebo through the Russo-Japanese War of 1904–1905 and remained the cornerstone of Japanese naval presence in southwestern home waters through World War II. Allied bombing during the Pacific war, including extensive raids in 1945, devastated the city while leaving much of the harbor infrastructure salvageable.

Following Japan's surrender, U.S. Marines of the V Amphibious Corps occupied Sasebo on September 22, 1945. The harbor immediately became a major U.S. demobilization, repatriation, and supply port, processing hundreds of thousands of returning Japanese servicemen and civilians from the Asian mainland. U.S. Fleet Activities Sasebo was formally established in 1946 under the Far East Command. The Korean War transformed Sasebo into the principal forward logistics base for U.N. naval forces: by 1952, more than 25,000 U.S. military personnel and tens of thousands of dependents and contractors were operating from Sasebo, supporting carrier task forces, amphibious operations at Inchon and Wonsan, and continuous maintenance and repair work in the original IJN dry docks.

Through the 1960s and 1970s, Sasebo's footprint was reduced as the Navy consolidated capability at Yokosuka, and by the 1980s the base had shrunk to a modest fleet logistics and ammunition function. The strategic decision to forward-deploy an amphibious squadron in the early 1990s reversed the trend. USS Belleau Wood arrived in 1991 as the lead amphibious assault ship of the newly forward-deployed Amphibious Squadron 11, accompanied by amphibious dock landing ships USS Germantown and USS Fort McHenry. The arrangement gave U.S. Marine Forces Pacific the ability to embark a Marine Expeditionary Unit and respond to crises in the Western Pacific in days rather than weeks.

The amphibious force at Sasebo has rotated through successive generations of big-deck amphibs: USS Belleau Wood was succeeded by USS Essex in 2000, USS Bonhomme Richard in 2012, USS Wasp in 2018, and USS America in 2020 — the first America-class amphibious assault ship to be permanently forward-deployed. Mine Countermeasures Squadron 7 forward-deployed Avenger-class minesweepers to Sasebo in the 1990s and continues to operate from the base today. The Sasebo-based amphibious ready group routinely embarks the 31st Marine Expeditionary Unit (31st MEU) from Marine Corps Base Camp Hansen on Okinawa, forming the U.S. military's only forward-deployed amphibious ready group / Marine expeditionary unit team and the principal forcible-entry force in the Indo-Pacific.

MAJOR COMMANDS & TENANT UNITS

• Commander, Fleet Activities Sasebo (CFAS)
• Commander, Amphibious Squadron 11 (CPR-11)
• Expeditionary Strike Group 7 forward elements
• USS America (LHA-6) Amphibious Ready Group — forward-deployed amphibious assault ship and supporting units
• Mine Countermeasures Squadron 7 (CMRON 7)
• Naval Munitions Command East Asia Division Detachment Sasebo
• U.S. Naval Hospital Branch Health Clinic Sasebo

LOCATION & GEOGRAPHY

HOST NATION CONTEXT

Like Naval Station Yokosuka, Fleet Activities Sasebo operates under the U.S.–Japan Treaty of Mutual Cooperation and Security (signed 1960) and the bilateral Status of Forces Agreement (SOFA) signed the same year. Day-to-day base operations involve close coordination with the Japan Maritime Self-Defense Force's Sasebo District Headquarters, which operates from the same harbor, and with the City of Sasebo and Nagasaki Prefecture authorities.

A substantial Japanese workforce is employed on base under the Master Labor Contract — including ship-repair workers in the dry docks, security personnel, and base-support staff — making CFAS one of the largest single employers in Sasebo City. The Japanese government provides Host Nation Support funding under the bilateral Special Measures Agreement, helping cover utility, labor, and facility costs.

U.S. military personnel and SOFA-status family members enter Japan with no-fee tourist or official passports and a SOFA stamp; civilian visitors require a standard Japanese visa or visa waiver and must be sponsored for base access. Liberty in Sasebo City and surrounding Nagasaki Prefecture is permitted under standing 7th Fleet liberty policy.

NOTABLE EVENTS

1. 1889
   Imperial Sasebo Naval District

   Imperial Japanese Navy establishes Sasebo as one of four principal naval districts, anchoring the IJN presence in southwestern Japan.
2. 1945
   U.S. Occupation

   Following Japan's surrender, U.S. Marines of the V Amphibious Corps occupy Sasebo. The harbor becomes a major U.S. demobilization and repatriation port.
3. 1946
   U.S. Fleet Activities Sasebo

   U.S. Naval Activities Sasebo formally established under the Far East Command.
4. 1950
   Korean War Hub

   Through the Korean War (1950–1953), Sasebo serves as the principal logistics, repair, and staging port for U.N. naval forces operating off Korea — peak personnel exceed 25,000.
5. 1991
   Forward-Deployed Amphibs

   USS Belleau Wood and Amphibious Squadron 11 forward-deployed to Sasebo, beginning the modern forward amphibious presence.
6. 2018
   America-class Arrival

   USS Wasp arrives at Sasebo as the lead forward-deployed amphibious assault ship, succeeded in 2020 by USS America (LHA-6) — first America-class big-deck amphib forward-deployed.

NEARBY BASES

FREQUENTLY ASKED QUESTIONS

SOURCES

• Wikipedia: United States Fleet Activities Sasebo
• CNIC — Commander, Fleet Activities Sasebo
• U.S. 7th Fleet — Amphibious Force
• U.S. Department of State — U.S.–Japan Relations