The competitors are from Hanoi, Thanh Hoa, Binh Duong and Ho Chi Minh City City, including seven-time world champion Nguyen Tran Duy Nhat.
According to head coach Giap Trung Thang, with his skills and experience, Nhat can bring home his world eighth gold medal in the 60kg class.
The event attracted more than 1,000 martial artists, who will compete in 15 weight classes until the event ends on July 29.
The Muay Thai World Championships 2019 is the second qualifying event for the World Games 2021 in the US.
The contest follows the concept of Olympic-system tournament. To win gold, a player has to go through the qualifying, quarter-final, semi-final and final (depending on the number of athletes participating in a particular class).