This is Volume I of the Final Report of the Forty-fifth Antarctic Treaty Consultative Meeting (ATCM) held in Helsinki, Finland, 29 May - 8 June 2023. This volume includes Part I (ATCM Final Report, Report of the Committee for Environmental Protection) and Part II Measures, Decisions and Resolutions adopted at this meeting. This edition is written in the English language. There are also editions in French, Russian and Spanish. More information at www.ats.aq