Since the end of WWII—culminated by the first use of nuclear weapons by one nation against another—the United States has forged a close security partnership with Japan. Today, Japan stands as America’s closest and most militarily capable ally in the Asia-Pacific region. Central to this alliance is the presence of numerous U.S. military bases in Japan, which play a vital role in defense, deterrence, and regional stability.
Let’s take a closer look at the major American military bases in Japan and their missions.
How Many US Military Bases Are in Japan?
United States Forces Japan (USFJ) utilizes all or part of 120 military installations in Japan.
There are more overseas US bases in Japan than in any other nation. For this article, we will only look at major US military installations in Japan.
How Many Major Military Installations are in Japan?
There are 10 major US military installations in Japan, with the island of Okinawa hosting the largest concentration of US bases in that nation.
Kadena Air Base, Okinawa, Japan
Kadena AB is the largest US installation in Japan.
It is home to the 18th Wing that is tasked with defending US and Japanese mutual interests by providing a forward power projection platform with integrated, deployable, combat power.
The Wing operates a fleet of combat-ready aircraft to perform air superiority, aerial refueling, airborne warning and control, and combat search and rescue functions.
In addition, a force of 8,000 trained Airmen is postured to support Air Force commitments in the Pacific region as well as US military commitments around the world. The total base population of 23,000 from five major commands also includes family members, US civilians, Japanese base workers, and contractors.
The 18th Wing is responsible for F-15s, KC-135s, E-3s, and HH-60s valued at more than $4 billion, as well as other equipment and capital assets valued at nearly $2 billion. The base also provides infrastructure support to Army, Navy, and Marine Corps forces assigned to or transiting Kadena.
Kadena AB also hosts associate units from five other Air Force major commands, the US Navy, and numerous other Department of Defense agencies and direct reporting units. In addition to the aircraft of the 18th Wing, associate units operate permanently assigned, forward-based, or deployed aircraft from Kadena on a daily basis.
Yokota Air Base, Western Tokyo, Japan
Yokota AB is located about 28 miles northwest of Tokyo and serves as a critical logistics hub and the primary US military port for the Indo-Asia-Pacific region. It hosts US Forces Japan, Fifth Air Force, and the 374th Airlift Wing, which serves as the host wing for the base.
Established in 1940 as the Tama Army Airfield, the base provides global mobility through agile airlift operations, supporting passenger, cargo, and mail transport across the Pacific for the Department of Defense. It's also home to the Japanese Air Self-Defense Force’s Air Defense Command (ADC) headquarters, highlighting its role in regional defense.
The 374th Airlift Wing executes its rapid global mobility through agile airlift operations across the Indo-Asia-Pacific region. It is responsible to the 5th Air Force commander for C-130J and C-12J operations, including tactical air-land, airdrop, aeromedical, and distinguished visitor airlift.
As the primary Western Pacific airlift hub for peacetime and contingency operations, the wing provides airlift for the movement of passengers, cargo, and mail to all Department of Defense agencies in the Pacific area of responsibility and provides transport for people and equipment throughout the Kanto Plain and the Tokyo metropolitan area.
The base has a population of more than 12,000 people that includes more than 3,500 military personnel who work alongside US and Japanese civilian employees in support of 32 tenant units.
Yokosuka Naval Base, South Tokyo, Japan
Yokosuka Naval Base is located on a peninsula approximately 30 miles southwest of Tokyo. It is formally known as United States Fleet Activities Yokosuka or Commander Fleet Activities Yokosuka. Its mission is to maintain and operate base facilities for the logistic, recreational, administrative support, and service of the US Naval Forces Japan, Seventh Fleet, and other operating forces assigned in the Western Pacific.
Yokosuka NB is the largest strategically important US naval installation in the western Pacific. It is the home port for the USS George Washington, a nuclear-powered aircraft carrier.
Yokosuka NB is supported by more than 24,000 military personnel and US and Japanese civilian employees.
Marine Corps Air Station Iwakuni, Yamaguchi Prefecture, Japan
Marine Corps Air Station (MCAS) Iwakuni is located in Iwakuni City, Yamaguchi Prefecture, Japan. Hiroshima is the most notable city near MCAS and is located approximately 25 miles northeast of the base. MCAS Iwakuni is about 600 miles south of Tokyo. It is a joint-use base for both US and Japanese military units.
MCAS Iwakuni is the home of Marine Aircraft Group 12 (MAG-12). The Group contains the rotary and fixed-wing aircraft assets permanently assigned to the base. MAG-12 is home to three flying squadrons, an aviation logistics squadron, and a ground support squadron.
MCAS Iwakuni also hosts Carrier Air Wing 5 Carrier Air Wing Five (CVW-5), the Navy aircraft carrier air wing attached to the aircraft carrier USS George Washington. It was initially formed in 1943. It has participated in the Second World War, the Korean War, the Gulf War, Operation Southern Watch, the War in Afghanistan, and the War in Iraq. CVW-5 consists of eight squadrons and one Fleet Logistics Squadron detachment. The flying squadrons include F-18E/F fighters, F-35B Lightning II fighters, E-2D Hawkeyes, and EA-18G Growler aircraft.
MCAS Iwakuni has a diverse personnel population of around 13,000 to 15,000 people, including US Marines, sailors, and airmen, their families, and a significant number of Japanese national employees.
Sasebo Naval Base, Kyūshū, Japan
US Fleet Activities Sasebo is a United States Navy base in Sasebo on the island of Kyūshū. It provides facilities for the logistic support of forward-deployed units and visiting operating forces of the United States Pacific Fleet and designated tenant activities.
The important bilateral relationship between Japan and the United States that exists today is very much in evidence at U.S. Fleet Activities Sasebo, where ships of the Japan Maritime Self-Defense Force and the United States Seventh Fleet share this port.
The base is home to several permanently forward-deployed ships, including the USS America, USS Tripoli, USS New Orleans, USS Rushmore, and USS San Diego.
The total personnel at Commander Fleet Activities (CFAS) Sasebo is approximately 7,200, consisting of about 3,100 active-duty US Navy personnel, 2,400 family members, 1,450 Japanese employees, and 215 Department of Defense civilians. The Japanese Maritime Self-Defense Force (JMSDF) employs more than 60,000 people at Sasebo.
Misawa Air Base, Aomori Prefecture, Japan
Misawa AB is an air base of the Japan Air Self-Defense Force (JASDF), the United States Air Force, and the United States Navy located in Misawa, Aomori, in the northern part of the island of Honshū in Japan. It is located 425 miles north of Tokyo. The 35th Fighter Wing (35 FW) serves as the base’s host wing and possesses 48 F-16 aircraft split between two Fighter Squadrons. As the host wing, the 35 FW services both Japanese and American personnel.
Misawa is the only combined, joint service installation in the Western Pacific. It houses three U.S. military services (Air Force, Navy, and Army), as well as the JASDF. The base is home to 5,200 US military personnel, as well as 350 US civilian employees and 900 Japanese national employees.
Naval Air Facility Atsugi, Kanagawa Prefecture, Japan
Naval Air Facility (NAF) Atsugi is a joint Japanese-US naval air base located in the cities of Yamato and Ayase in Kanagawa, about 23 miles southwest of Tokyo.
It is the largest US Navy air base in the Pacific and once housed all of the squadrons of CVW-5.
After most of the squadrons from CVW-5 relocated to MCAS Iwakuni, only its two helicopter squadrons remained at NAF Atsugi. In addition to the two CVW-5 helicopter squadrons, NAF Atsugi is also home to Helicopter Maritime Strike Squadron 51, which provides detachments of MH-60R helicopters to forward-deployed US Navy guided missile cruisers, guided missile destroyers, and frigates at the nearby Yokosuka NB.
NAF Atsugi has a total of about 10,000 personnel and their families, encompassing US military members, JMSDF personnel, and both Japanese and US civilian employees. This figure reflects the base's status as a joint-use facility with the JMSDF
Camp Zama, Kanagawa Prefecture, Japan
Camp Zama is a US Army garrison in Kanagawa Prefecture about 23 miles southwest of Tokyo and only four miles from NAF Atsugi. Camp Zama serves as the home of US Army Japan (USARJ) and as a key partner for the Japan Ground Self-Defense Force (JGSDF). Camp Zama is also home to I Corps (Forward), the US Army Aviation Battalion Japan "Ninjas," the 311th Military Intelligence Battalion, the Japan Engineer District (US Army Corps of Engineers), the 78th Signal Battalion, and the Bilateral Coordination Department and 4th Engineer Group of the JGSDF.
Camp Zama has a population of approximately 4,000 personnel, including US soldiers, civilians, contractors, and their families, with Japanese Nationals making up more than half of the workforce on the site.
Marine Corps Air Station Futenma, Okinawa, Japan
MCAS Futenma is a United States Marine Corps base located in Ginowan on the island of Okinawa. It is home to the 1st Marine Aircraft Wing (MAW) and other units and has been a US military airbase since the defeat of the Japanese Imperial Army in the Battle of Okinawa in 1945.
Marine Corps pilots and aircrew are assigned to the base for training and providing air support to other land and sea-based Marines in Okinawa and throughout the Asia-Pacific region. MCAS Futenma is part of the Marine Corps Installations Pacific command.
MCAS Futenma is tasked with operating a variety of fixed-wing, rotary-wing, and tilt-rotor aircraft in support of the III Marine Expeditionary Force, the Japan-US defense alliance, and many allies and treaty partners in the region.
MCAS Futenma is home to approximately 3,000 Marines and other US personnel.
US Army Garrison Okinawa, Okinawa, Japan
US Army Garrison Okinawa is a US Army facility located in Yomitan on the island of Okinawa. Home to the US Army on Okinawa, 10th Support Group (Regional), along with the 1st Battalion, 1st Special Forces Group (Airborne), 247th Military Police Detachment, and the 349th Signal Company, provides support to all other US military services on the island. Formerly named “Torii Station,” the garrison was re-designated in March 2014
US Army Garrison Okinawa has a total population of approximately 5,000 people, which includes military personnel, their families, civilians, and contractors. The station serves as the main Army installation on the island.
The Key Missions of US Forces Japan
The key missions of USFJ are to strengthen the US-Japan alliance, provide regional stability, and deter or defeat threats to Japan.
USFJ is currently undergoing a significant transformation to function as a Joint Force Headquarters (JFHQ), enabling more seamless and integrated operations with the Japan Self-Defense Forces (JSDF).
The American military bases in Japan serve as the backbone of the U.S.-Japan security alliance. They enable rapid response to crises, ensure regional stability, and project American power throughout the Indo-Pacific.
As USFJ transforms into a Joint Force Headquarters (JFHQ), cooperation with the Japan Self-Defense Forces will only deepen—ensuring that these bases remain critical to both nations’ defense strategies.
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