ach province in Thailand has its own restrictions for domestic travel. According to the data given by Nok Air, most of the provinces require 2 doses of Sinovac/Sinopharm for more than 14 days or 1 dose of Astra Zeneca/Pfizer/Moderna/ J&J for more than 14 days but some provinces require more shots with different periods of time.
Therefore, it is highly recommended to check the requirements of each destination province with an airline before traveling domestically at the moment.
Source: Nok Air as of 31 Aug 2021.
Original table in Thai by Nok Air Click Here