They are mostly the provinces that the Centre for Covid-19 Situation Administration has classified as red code.
The provinces are: Bangkok, Tak, Nonthaburi, Pathum Thani, Ayutthaya, Saraburi, Lopburi, Singburi, Ang Thong, Nakhon Nayok, Kanchanaburi, Nakhon Pathom, Ratchaburi, Suphan Buri, Prachuap Khiri Khan, Phetchaburi, Samut Songkhram, Samut Sakhon, Chachoeangsao, Prachinburi, Sa Kaeo, Samut Prakarn, Chanthaburi, Chonburi, Trat, Rayong, Chumphon and Ranong.
During the closure, the schools will have to provide courses via a long-distance learning method or an online channel.