It depends on the ticket type. Opening tickets are valid from the opening day to 26 April 2025. First-half period tickets are valid from the opening day to 18 July 18 2025. Summer passes are valid from 19 July to 31 August 2025. Season passes are valid from the opening day to 3 October 2025. Weekday tickets are valid only on weekdays during the Expo period, excluding weekends, holidays, and substitute holidays.

https://ticket.expo2025.or.jp/en/faq/