Although the Japanese government did not announce an exact date, the reopening is planned for “the beginning of September”. The reopening will consist of three stages, the first stage will include the essential travelers, the second stage will inlcude students, and the third stage will include tourists. All visitors will either have to present a negative COVID-19 test result taken within 72 hours before arrival and take another one upon arrival or quarantine for 14 days. A list of countries authorized to visit the country will be announced, most probably the initial list will include Singapore, Vietnam, Thailand, Australia, New Zealand, Taiwan, South Korea, China, and Malaysia.
Source: Travel Off Path