His Majesty King Rama X promulgated the new constitution in a ceremony at the Ananta Samakhom Throne Hall on Thursday, Chakri Day.
The Constitution was presented to the King who signed it and after that it was returned to Prime Minister Prayut Chan-o-cha.
Participants in the ceremony included Prayut government, members of the Royal Family, privy councillors, Cabinet members, foreign diplomats, National Legislative Assemblyand Constitution Drafting Commission members, the Supreme Court president, heads of independent organisations, and senior military commanders and civil servants.
A court secretary then will read out a royal statement announcing the promulgation of the 2017 constitution.
That is to be followed by three rounds of 21-gun salutes by the Army, Navy and Air Force.