This is the first official visit of a RoK President to Thailand and Myanmar since 2012, and the first-ever state visit to Laos, according to Yonhap news agency.
The RoK news agency said President Moon Jae-in is scheduled to hold summit talks with Prime Minister Prayuth Chan-ocha on September 2.
He will head to Myanmar on September 4, where he will have meetings with State Councilor Aung San Suu Kyi and President Win Myint.
During the state visit to Laos from September 5, the RoK President will meet with President Bounnhang Vorachith and Prime Minister Thongloun Sisoulith.