| 1972 | Establishment of Tsurugamine Seminar (renamed as TsuruSemi) |
| 1984 | Opening of Miyazawa Gakuen (renamed SEISA Gakuen) Assigned by the Minister of Education |
| 1985 | Establishment of Kokusai Gakuen Education Institute |
| 1986 | Opening of Peter Pan Kindergaten |
| 1987 | Opening of Yokohaama International College Of Social Welfare |
| 1993 | Opening of SEISA Gakuen High School division Subaru School |
| 1995 | Opening of SEISA Gakuen High School division Aoba School |
| Establishment of International Miyazawa Education Institution | |
| Establishment of Yokohama-Bhutan Friendship Association | |
| 1997 | Opening of SEISA Gakuen High School division Shonan School |
| 1998 | Opening of SEISA Gakuen High School College Division |
| Establishment of LD Consultation Center, Kanagawa | |
| 1999 | Establishment of Hoshi-no-shima Co., ltd (Agricultural production corporation) |
| Opening of SEISA Kokusai High School | |
| Opening of SEISA Kokusai High School Sapporo & Yokohama & Osaka & Fukui District-core Centers | |
| Opening of Shonan Magic Co., ltd | |
| 2000 | Opening of SEISA Kokusai High School Koriyama District-core Center |
| Establishment of Futuro (NPO Corporation) | |
| 2001 | Opening of SEISA Kokusai High School Fukuoka-higashi District-core Center |
| Opening of Okudera Sports Academy | |
| Opening of Nogawa-minamidai nursery school | |
| 2002 | Opening of SEISA Kokusai High School Toyama District-core Center |
| 2003 | Opening of Aobadai Kindergarten |
| Opening of SEISA Kokusai High School Hamamatsu District-core Center | |
| Opening of SEISA Gakuen Junior High School division Shonan School | |
| 2004 | Opening of SEISA University |
| Opening of SEISA Kokusai High School Sendai & Tachikawa & Hiroshima & Okinawa District-core Centers | |
| 2005 | Opening of SEISA Junior High School |
| Opening of SEISA Kokusai High School Tobetsu & Yokohama-Kamoi District-core Center | |
| Establishment of SEISA Education Research Center (NPO) | |
| 2006 | Opening of SEISA High School |
| Opening of SEISA Kokusai High School Atsugi District-core Center | |
| 2007 | Opening of SEISA Kokusai High School Fukuoka-chuo District-core Center |
| Establishment of SEISA Comprehensive Education Research Center | |
| Opening of SEISA Gakuen High School division Yokohama-portside & Omiya Schools | |
| Opening of After school Kids Club | |
| 2009 | Opening of SEISA Shonan-Oiso Campus (SEISA Group Head Office) |
| 2010 | Opening of SEISA Kokusai High School Obihiro Campus |
| Opening of SEISA Shonan-oiso Stadium | |
| Establishment of FGC – Foundation for Global Children (Public Interest Incorporated Foundation) | |
| Establishment of Space Weather Association (General Incorporated Corporation) | |
| Establishment of Shin-seisakuza Theatrical Company (NPO Corporation) | |
| Opening of SEISA Takao Campus | |
| 2011 | Opening of SEISA Gakuen High School & Junior High school division Hokuto School |
| Opening of SEISA Kokusai High School Nagoya Campus | |
| Opening of Twinkle Uenogawa Nursery School | |
| 2012 | Opening of SEISA Nagoya Junior High School |
| Opening of SEISA Shonan-Oiso Comprehensive Community Sports Club (General Incorporated Corporation) | |
| Opening of SEISA Hakone-Sengokuhara Comprehensive Community Sports Club (General Incorporated Corporation General Incorporated Corporation) | |
| Opening of SEISA Momiji Campus | |
| Opening of SEISA Hakone Campus | |
| 2013 | Opening of Twinkle Seya & Kunugisaka Nursery Schools |
| Establishment of SEISA Sapporo Educaiton Center (NPO Corporation) | |
| Opening of SEISA University Grad School | |
| Opening of SEISA Kokusai High School Kagawa (Takamatsu School & Marugame School) Campus Opening of SEISA Kokusai High School Sapporo Educaiton Center |
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| 2014 | Opening of SEISA Momiji Junioir High School |
| Establishment of Foreign Care Workers Association (General Incorporated Corporation) | |
| Starting operation of Japan Professional School of Education | |
| 2015 | Opening of SEISA Kokusai High School Shonan District-core Center |
| Opening of SEISA Kokusai High School Nagoya District-core Center | |
| Medical Care and Education Future Creation Research Center | |
| 2016 | Opening of SEISA Kokusai High School Takamatsu District-core Center Opening of SEISA Kokusai High School Kokura & Naha Campuses |
| Opening of SEISA Seagull Agra Sara Garment (Chittagong, Bangladesh) | |
| Opening of SEISA Athletic Club | |
| Establishment of Kanagawa Overseas Cooperation Volunteers Supporting Association | |
| Starting of administrating of SEISA Lake Arena | |
| 2017 | Opening of SEISA Kokusai High School Sapporo-kita & Obihiro District-core Centers Opening of SEISA Kokusai High School Kawaguchi Campus Opening of SEISA Kokusai High School Asahikawa Schooling Center |
| Starting of SEISA Dohto University | |
| Opening of SEISA University Grad School Practice of education Course (Integrating Japan Professional School of Education into SEISA University Grad School) | |
| 2018 | Opening of SEISA Kokusai High School Marugame, Odawara District-core Centers & Shizuoka Campus |
| 2019 | Changed Sapporo District-core center of SEISA Kokusai High School to Headquarters |
| Opening of SEISA Kokusai High School Ashibetsu, Shizuoka, Kawaguchi District-core centers & Kita-kyushu, Asahikawa Campus | |
| SEISA Junior High School relocated to a new school in Kirigaoka | |
| 2020 | Opening of SEISA Kokusai High School Kofu District-core center and Kita-hiroshima & Toyama campus |
| Opening of SEISA Gakuen Hokuto Primary School Division | |
| Opening of SEISA University Graduate School of Education Doctoral Course | |
| 2021 | Opening of SEISA Kokusai High School Kita-hiroshima and Naha District-core Centers |
| Opening of SEISA Gakuen Omiya Junior High School Division | |
| Establishment of Educational Corporation SEISA ECEC* KIDS planet (Peter Pan Kindergarten and Aobadai Kindergarten were transferred from Kokusai Gakuen Education Institute) * ECEC: Certified Center for Early Childhood Education and Care |
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| 2022 | SEISA Group Celebrates 50th Anniversary |
| Opened SEISA Kokusai High School Kita-kyushu District-core Center | |
| Opened SEISA Kokusai High School Toyama District-core Center | |
| Opened SEISA Kokusai High School "Cloud School" | |
| Established SEISA High School Narrow Correspondence Course | |
| Started operation of day-care center at Tokyo Metropolitan High School (NPO SEISA Education Research Center) | |
| Started operation of "Yuyuyu" Educational Support Center in Memuro-cho (Seisa Kokusai High School Obihiro District-core Center) | |
| Established Educational Corporation SEISA (SEISA Junior High School, SEISA High School and SEISA Nagoya Junior High School were transferred from Kokusai Gakuen Education Institute) | |
| Established Joint Venture Campany RAFT PROJECTS (commercialization of classes) |
© SEISA GROUP
