On January 7th 2022, Mr. Wakamiya Kenji, Minister for the World Expo 2025, Minister Wakamiya had a press conference, and announced that there are 5 countries and 1 international organization newly confirmed their participation in the Expo; Azerbaijan, Estonia, Australia, Serbia, Turkey and ASEAN Secretariat.
Also, Minister Wakamiya received a courtesy call by H.E. Mr. Korkut Gungen, Ambassador of Turkey to Japan. At the meeting, Ambassador Gungen expressed the intention of the Turkey to participate in the Expo 2025 Osaka, Kansai. Minister Wakamiya wholeheartedly welcomed the Turkey's participation, and confirmed continued close cooperation towards a success of Expo 2025 Osaka, Kansai, Japan.
This makes in total of 72 countries and 6 international organizations that have confirmed their participation, as of January 7th 2022.
For the detail, please check the list of participants on the website of Ministry of Foreign Affairs.
Ministry of Foreign Affairs "Confirmed Participants for the Expo2025"
https://www.mofa.go.jp/ecm/ec/page22e_000942.html