Tourism and Sports Minister Phiphat Ratchakitprakarn announced the move after discussions with Bangkok Governor Aswin Kwanmuang.
The proportion of people vaccinated in all Bangkok districts is expected to reach the 70 per cent threshold for reopening by the end of this month.
Phiphat said all Bangkok districts will open to foreign travellers at the same time.
He added that four other tourism areas – Hua Hin, Cha-am, Chiang Mai and Pattaya – will open on October 1 if preparations go to plan.