Marine Corps Air Station Iwakuni Marine Corps Air Station Iwakuni or MCAS Iwakuni is a United States Marine Corps air station located in the Nishiki river delta , southeast of the Iwakuni Station in the city of Iwakuni , Yamaguchi , Japan . History . The Japanese government bought a large portion of what is today MCAS Iwakuni in 1938 , with the view of establishing a naval air station . They commissioned the new base 8 July 1940 . When World War II started , the Iwakuni air station was used as a training and defense base . The station housed 96 trainers and 150 Zero fighter planes on the airstrip . In September 1943 , a branch of the Etajima Naval Academy was established here , with approximately 1 , 000 cadets undergoing training in the Basic , Junior and Senior Officer ' s schools at any one time . American B - 29 ' s bombed Iwakuni in May and August 1945 , concentrating on the oil refinery and Rail Transport Office or train station areas . The last air raid took place just a day before the war was brought to a close . The first allies to reach Iwakuni at the war ' s end were a group of U . S . Marines who had signed papers ending the conflict for the Japanese air base . After the end of World War II , various military forces from the United States , Britain , Australia , and New Zealand occupied the base and it was repaired by No . 5 Airfield Construction Squadron RAAF . It was designated a Royal Australian Air Force Base in 1948 . Then in 1952 , the base officially became a United States military base . The Americans first occupied the base in 1950 to use it as a springboard for aircraft heading to the Korean War . It was revealed in 2010 that in 1966 nuclear weapon s were moved to the base for storage from Okinawa . When U . S . ambassador to Japan Edwin O . Reischauer learned of the presence of the weapons , which was a violation of the Treaty of Mutual Cooperation and Security between the United States and Japan , he told the United States Department of State that if the weapons were not removed within 90 days he would resign and go public with the information . The weapons were removed shortly thereafter . On 14 July 1970 , African - American soldiers and some anti - war soldiers raised a riot against the Vietnam War on the base . It is currently home to around 5 , 000 United States Marines ( including family members ) . The base is detailed for Marine pilot training and air patrol , using F / A - 18 Hornet fighter - attack aircraft among others in compliance with the Treaty of Mutual Cooperation and Security obligations to protect Japan . MCAS Iwakuni is also shared with the Japanese Maritime Self Defense Force . MCAS Iwakuni has an air station that many people in Iwakuni want to be made into a public international airport . MCAS Iwakuni is home to a Department of Defense school , Matthew C . Perry ( Elementary and High School ) . In 2014 , it is planned to move the U . S . Carrier Air Wing from Atsugi to Iwakuni which will further increase the size of the base . However , due to construction delays , the Navy will continue to operate out of NAF Atsugi until 2017 . The USMC ' s aircraft procurement plan for fiscal year 2010 revealed that the Corps plans to station 16 F - 35B aircraft at Iwakuni beginning in the fall of 2015 to replace the AV - 8 and F / A - 18 aircraft currently stationed at the base . The F - 35B ' s engines are louder than those of the AV - 8 and F / A - 18 which may have an impact on the local community . A new off - shore runway opened at the base on 30 May 2010 . The new runway is 2 , 440 meters in length . Since 2000 , the base has killed approximately 25 , 000 Black Widow spiders which apparently came to the base in cargo and luggage of Americans assigned to the base . The spiders are not native to Japan , so local American and Japanese authorities are attempting to keep them from spreading beyond the base . 203 of the spiders were found and killed between October 2009 and January 2010 . Commercial Services . Regular commercial service started from December 13 , 2012 with a civilian airport terminal built to accommodate commercial flights . It was initially projected that up to 430 , 000 passengers would use the airport each year , and in the first seven months of operations the airport handled over 200 , 000 passengers , with average load factor s between Iwakuni and Tokyo exceeding 70 % during June 2013 . Since IATA airport code IWJ , formerly assigned to Iwakuni , was already reassigned to Iwami Airport , new IATA code of IWK was assigned to Iwakuni . The inaugural flight was operated by All Nippon Airways from Haneda Airport . Also , Iwakuni Airport will be called by its official nickname " Iwakuni Kintaikyo Airport " , named after the Kintaikyo bridge near the airport . Friendship Day . Every year on 5 May , Japanese Nationals and U . S . service members , government employees and their families officially celebrate their long - standing friendship by opening the gates of MCAS Iwakuni for one of Japan ' s largest air show s dedicated to enhancing the friendship of the two nations . The event , entitled Friendship Day , hosts an average 250 , 000 visitors who travel from all over Japan .