May 1１, 2021 Press Release Idemitsu Kosan Co., Ltd

Change in Directors and Auditors

Idemitsu Kosan Co.,Ltd. Hereby announces that the Board of Directors has decided to proposes changes to the directors and the auditors, as described below, at a board meeting held on May 11, 2021. We expect that this proposal will be approved at the 106th annual shareholders meeting scheduled to be convened on June 23, 2021. The approval will be followed by a formal decision by the Board of Directors.

1. Change of Directors and Auditors （１）Appointment Noriaki Sakai Director, Managing Executive Officer Yumiko Noda Outside Director Maki Kado Outside Director Tsutomu Yoshioka Audit & Supervisory Board Member

（２）Retirement Katsuaki Shindome Current: Director（Chair of Directors Meeting） Mackenzie Clugston Current: Outside Director Norio Otsuka Current: Outside Director Yuko Yasuda Current: Outside Director Kenji Takahashi Current: Audit & Supervisory Board Member

2. Effective Date of the Proposed Changes June 23, 2021

- Contact for Inquiries on this subject - Idemitsu Kosan Co.,Ltd., Public Relations Department Public Relations Section https://www.idemitsu.com/jp/contact/advertising_flow/index.html 【Reference】 Management of Idemitsu Kosan Co., Ltd. （Proposed on June 23, 2021)

Directors Shunichi Kito Representative Director & Chief Executive Officer

Takashi Matsushita Representative Director, Executive Vice President Assistant to Chief Executive Officer in charge of Manufacturing & Technology, , Functional Materials, Intellectual Property/Research, and Project Susumu Nibuya Representative Director, Executive Vice President Assistant to Chief Executive Officer in charge of Resources, Corporate Planning, External Affairs and Public Relations, ESG, Digital Innovation, Special Missions, and Internal Communication Department Atsuhiko Hirano Director, Managing Executive Officer Assistant to Chief Executive Officer in charge of Business and Power & Renewables Business

Noriaki Sakai Director, Managing Executive Officer Chief Financial Officer (Accounting Department and Finance Department),in charge of Procurement (Procurement Department), Head of Safety & Environmental Protection Headquarters and Head of Quality Assurance Headquarters Masakazu Idemitsu Director (part-time)

Kazunari Kubohara Director (part-time)

Takeo Kikkawa Outside Director

Mitsunobu Koshiba Outside Director Yumiko Noda Outside Director

Maki Kado Outside Director

Audit & Supervisory Board Members

Toshiyuki Tanida Audit & Supervisory Board Member

Tsutomu Yoshioka Audit & Supervisory Board Member Taigi Ito Outside Audit & Supervisory Board Member

Kenji Yamagishi Outside Audit & Supervisory Board Member 【Reference】 Biography of Candidates of Directors

Name Noriaki Sakai

Biography April 1987 Joined the Company July 2010 Deputy General Manager of Tokuyama Refinery and Deputy General Manager of Tokuyama Plant

July 2012 Deputy General Manager of Human Resource Department, Health Insurance Union President and Corporate Pension Fund President

July 2015 Deputy General Manager of Accounting Department and Corporate Pension Fund June 2017 General Manager of Accounting Department July 2018 Executive Officer and General Manager of Accounting Department April 2019 Executive Officer and General Manager of Finance Department July 2020 Senior Executive Officer and Chief Financial Officer June 2021 Director, Managing Executive Officer (proposed) Name Yumiko Noda

Biography 1982 Seninor Superviser, Tokyo Branch, Bank of America Corporation 1990 Manager, Project Finance Department, The Long-Term Credit Bank of Japan Ltd. 1991 Vice President, New York Branch, The Long-Term Credit Bank of Japan Ltd. 1996 Deputy General Manager, London Branch The Long-Term Credit Bank of Japan Ltd. 1998 Director, PwC (UK) 2000 Partner, Head of PPP and Privatization, PwC Financial Advisory Service Co., Ltd. 2007 Deputy Mayor, Yokohama City 2010 Senior Fellow, Center for Japanese Studies, Tsinghua University (Beijing) 2011 Partner, Head of PPP and Infrastructure Asia Pacific, PwC Advisory 2017 President and Representative Director, Veolia Japan K.K. 2020 Chairman and Representative Director, Veolia Japan K.K. 2021 Outside Director (proposed） Name Maki Kado

Biography 1992 NEC Corporation 1996 United Feature Syndicate Inc. Japan Branch 2000 Microsoft Product Development Inc. (Japan)

2005 Microsoft Corporation Inc. (US) Headquarters

2013 General Manager of Purchasing, salesforce.com Co.,Ltd. 2015 Representative Director and President, Coca- Cola Business Services Co.,Ltd. 2015 Representative Director and President, Coca- Cola Business Sourcing Co.,Ltd. 2016 Coca-Cola Cross Enterprise Procurement Group Budget Committee Chair (CFO) 2017 Executive Officer, Head of Procurement, Coca-Cola Bottlers Japan Inc. 2019 Executive Officer, Head of Business Transformation and Head of Procurement, Coca-Cola Bottlers Japan Inc. 2020 Executive Officer, Head of Business Transformation, Coca-Cola Bottlers Japan Inc. and Executive Officer, Executive Business Manager, Coca-Cola Bottlers Japan Holdings Inc.

2021 Outside Director (proposed) 【Reference】 Biography of Candidates of Auditor

Name Tsutomu Yoshioka

Biography April 1984 Joined K.K. September 2002 General Manager of Branch Office April 2005 Representative Director, President, Shoseki Gas K.K. July 2008 Representative Director, President, Enessance Holdings Co., Ltd. March 2011 Executive Officer in charged of Accounting, Finance and Credit Management April 2015 Executive Officer and General Manager of Petroleum Business Division Metropolitan Area Branch March 2017 Audit & Supervisory Board Member April 2019 Senior Executive Officer in charged of Information Systems, General Affairs, Safety & Environmental Protection and Quality Assurance, Idemitsu Kosan Co., Ltd

October 2020 Senior Executive Officer in charged of Information Systems, General Affairs, Credit and Financial Risk Management and Internal Control Promotion

June 2021 Audit & Supervisory Board Member (proposed)