Thailands Centre for Covid-19 Situation Administration (CCSA), the task force chaired by Prime Minister Prayut Chan-o-cha, has decided: Fully vaccinated international visitors from 1st March don't need a hotel booking and a PCR test for the fifth night after arrival anymore. Instead they can do a self-antigen test.
Another decision: The minimal medical insurance coverage for visitors is reduced to no less than $20,000 from $50,000 from 1st March. Read details of the new regime.
Who wants to enther Thailand before 1st March still has to book a SHA Extra plus hotel for the 5th night and stay there until a negative PCR-test-result has arrived. See: Thailand Test and Go from 1st February
