History
| April 1924 | Hamako Matsudaira founded Kanto Koto Jyogakko at 416 Jyunisha, Tsunohazu, Shimo-Yodobashi, Tokyo. |
|---|---|
| July 1937 | Vice-principal Genshiro Hosoya (Hamako Matsudaira's older brother) passes away in an attack during the Tongzhou Incident while staying in China. |
| April 1946 | Name was changed to Kanto Jyogakuen Chutobu (Junior High School) in accordance with reforms in the school system. |
| April 1948 | Built the Kanto Jyogakuen Kotobu (High School) adjoining the junior high. |
| April 1950 | Added the Sumire Kindergarten |
| 1955 | Changed the legal name to Kanto Jyoshi Koto Gakko. |
| April 1967 | Changed the legal name to Kanto Jogakuen and the school name to Kanto Jyoshi Koto Gakko |
| April 1969 | Entered a tie-up with Isetan Department Store and began practical training classes |
| October 1979 | Entered a tie-up with Lincoln Memorial University in Tennessee, U.S.A. |
| April 1982 | Established the English Department |
| April 1984 | Established the Department of Performing Arts |
| April 1985 | Entered a tie-up with Soochow University in China |
| April 1986 | Changed the legal name to Kanto Hama Kokusai Gakuen and the school name to Kanto International Senior High School Changed the name of the English Department to the English Course, Department of Foreign Studies Established the Chinese Course in the Department of Foreign Studies Began coeducational programs in the Department of Foreign Studies and the Department of Performing Arts |
| June 1988 | Entered a tie-up with Beijing Language and Culture University in China |
| July 1990 | Entered a tie-up with the Far Eastern National University in Vladivostok, Russia |
| March 1991 | Entered a tie-up with Peking University in China |
| April 1991 | Established the Russian Course in the Department of Foreign Studies |
| April 1993 | Finished a portion of the Katsuura Training Center in Chiba and began using it for school programs |
| October 1997 | First World School International Forum |
| April 1998 | Changed the legal name to Kanto International School Began a coeducational program in the Department of General Education |
| May 1998 | Entered a tie-up with I-Ning High School in Taichung, Taiwan |
| September 1998 | Entered a tie-up with Invicta Grammar School in Kent, England |
| March 1999 | Entered a tie-up with St. Paul's School in Queensland, Australia |
| April 2000 | Established the Korean Course in the Department of Foreign Studies |
| April 2003 | Designated as a Super English Language High School by the Ministry of Education, Culture, Sports, Science and Technology |
| April 2004 | Established an Overseas University Exchange Studies Class in the English Course. |
| April 2005 | Established a Science Course in the Department of General Education |
| April 2007 | Established Thai, Indonesian and Vietnamese Courses in the Department of Foreign Studies |
| April 2015 | Suspension of Recruitment for the Department of Performing Arts |
| April 2018 | Established a Humanities and Science Course and Japanese Culture Course in the Department of General Education. |
| April 2023 | Established Italian and Spanish Courses in the Department of Foreign Studies |
| April 2024 | Established the French Course in the Department of Foreign Studies |