| May, 1889 |
Mr. Jinnojo Ohkubo, an assemblyman of Kagawa Pref. Diet, advocates the plan of bridges between Honshu and Shikoku. |
| March, 1914 |
Mr. Toranosuke Nakagawa, a member of the Diet in Tokushima election district, submits "Plan of a bridge crossing Naruto Strait" to the national diet. |
| April, 1940 |
Mr. Chujiro Haraguchi, the head of Kobe office, the Department of the Interior, proposes the bridge plan crossing Naruto Strait. |
| August, 1953 |
Mr. Chujiro Haraguchi, the mayor of Kobe city, encourages to carry out the site survey for Akashi-Kaikyo Bridge. |
| April, 1955 |
Japan National Railways initiates a field investigation on the Honshu-Shikoku Awaji line (A route). |
| May, 1955 |
Accident of Utaka Ferry Boat "Shiunmaru" happened (the death toll climbs to 168). |
| April, 1959 |
The Ministry of Construction (MOC) initiates a field investigation on A, C, D and E routes. |
| April, 1961 |
The MOC initiates a field investigation on B route and Japan National Railways initiates a field investigation on B, C, and D routes. |
| May, 1969 |
New Comprehensive National Development Plan is established (the routes of three expressways are finalized). |
| July, 1970 |
Honshu-Shikoku Bridge Authority (HSBA) is established to implement Honshu-Shikoku Bridge Projects. |
| September, 1973 |
Minister of MOC and Minister of Transport Ministry (MOT) indicate to make a basic construction plan of Honshu-Shikoku Bridge Projects. |
| October, 1973 |
Ministers of MOC and MOT accept the basic construction plan of the Projects. |
| November, 1973 |
The Honshu-Shikoku Bridge Expressway ground-breaking ceremony is postponed as part of the demand management policy. |
| December, 1975 |
Ground-breaking ceremony of Ohmishima Bridge in Nishi-Seto Expressway is held. |
| July, 1976 |
Ground-breaking ceremony of Ohnaruto Bridge in Kobe-Awaji-Naruto Expressway is held. |
| January, 1977 |
Ground-breaking ceremony of Innoshima Bridge in Nishi-Seto Expressway is held. |
| October, 1978 |
Ground-breaking ceremony of Seto-Chuo Expressway is held. |
| May, 1979 |
Ohmishima Bridge in Nishi-Seto Expressway is opened. |
| March, 1981 |
Ground-breaking ceremony of Hakata-Ohshima Bridge in Nishi-Seto Expressway is held. |
| December, 1983 |
Innoshima Bridge in Nishi-Seto Expressway is opened. |
| June, 1985 |
Ohnaruto Bridge in Kobe-Awaji-Naruto Expressway is opened. |
| April, 1986 |
Ground-breaking ceremony of Akashi-Kaikyo Bridge in Kobe-Awaji-Naruto Expressway is held. |
| May, 1986 |
Ground-breaking ceremony of Ikuchi Bridge in Nishi-Seto Expressway is held. |
| January, 1988 |
Hakata-Ohshima Bridge in Nishi-Seto Expressway is opened. |
| April, 1988 |
Seto-Ohashi Bridges conclude signed the sister bridge affiliation with Golden Gate Bridge in USA. |
| April, 1988 |
Seto-Chuo Expressway and JR Seto-Ohashi Line are opened. |
| May, 1988 |
Ground-breaking ceremony of Kurushima-Kaikyo Bridges in Nishi-Seto Expressway is held. |
| July, 1988 |
Seto-Ohashi Bridges conclude the sister bridge affiliation with Fatih Sultan Mehmet Bridge in Türkiye. |
| August, 1990 |
Ground-breaking ceremony of Tatara Bridge in Nishi-Seto Expressway is held. |
| December, 1991 |
Ikuchi Bridge in Nishi-Seto Expressway is opened. |
| March, 1997 |
the head office of HSBA is shifted to Kobe from Tokyo. |
| April, 1998 |
Akashi-Kaikyo Bridge in Kobe-Awaji-Naruto Expressway is opened. |
| June, 1998 |
Akashi-Kaikyo Bridge concludes the sister bridge affiliation with Great Belt Bridge in Denmark. |
| May, 1999 |
Shin-Onomichi Bridge, Tatara Bridge and Kurushima-Kaikyo Bridges in Nishi-Seto Expressway are opened. |
| May, 1999 |
Tatara Bridge concludes the sister bridge affiliation with Normandy Bridge in France. |
| May, 2003 |
Debt Relief Special Law of HSBA is issued (the national government succeeds to the debt of HSBA, 1.34 Trillion JPY, with interest). |
| June, 2004 |
Privatization Laws for Four Highway Public Corporations are issued. |
| October, 2005 |
Honshu-Shikoku Bridge Expressway Company Limited (HSBE) is established. |
| April, 2006 |
Nishi-Seto Expressway is fully completed. |
| May, 2008 |
Seto-Ohashi Bridges conclude the sister bridge affiliation with Oresund Bridge between Denmark and Sweden. |
| October, 2008 |
Setouchi Museum Network is established. |
| May, 2009 |
HSBE signs the Memorandum of Understanding with Korea Expressway Corporation. |
| July, 2009 |
HSBE signs the Memorandum of Understanding with Kobe University. |
| December, 2010 |
HSBE signs the Mutual Cooperation Agreement in Disaster with Hyogo prefecture. |
| April, 2011 |
HSBE signs the Mutual Cooperation Agreement in Disaster with Tokushima prefecture. |
| July, 2011 |
HSBE signs the Memorandum of Understanding with Japan Expressway International Company Limited. |
| August, 2012 |
HSBE signs the Mutual Cooperation Agreement in Disaster with Okayama prefecture. |
| August, 2012 |
HSBE signs the Mutual Cooperation Agreement in Disaster with Kagawa prefecture. |
| March, 2014 |
Honshu-Shikoku Bridge Expressway is incorporated into National Route Network. |
| January, 2015 |
A signing ceremony for a partnership agreement with the Japan Ground Self-Defense Force (Middle Army) is held. |
| March, 2017 |
A signing ceremony for a partnership and cooperation agreement with the Shikoku Railway Company is held. |
| February, 2018 |
Awajishima-chuo Smart Interchange is opened. |
| July, 2018 |
HSBE signs the Memorandum of Understanding with A/S Storebælt. |
| October, 2019 |
HSBE signs the Comprehensive Mutual Cooperation Agreement for Regional Revitalization along the Setouchi Shimanami-Kaido and the Mutual Cooperation Agreement in Disaster with Ehime prefecture. |
| November, 2019 |
HSBE signs the Mutual Partnership Cooperation Agreement for Regional Revitalization along the Setouchi Shimanami-Kaido and the Mutual Cooperation Agreement in Disaster with Hiroshima prefecture. |
| March, 2020 |
Awaji-kita Smart Interchange is opened. |
| July, 2025 |
Kurushima-Kaikyo Bridges conclude the sister bridge affiliation with Osmangazi Bridge in Türkiye. |
