Thousands of Thai army cadets, university students and a handful of volunteers performed a record-breaking Muay Thai "wai khru" ceremony on Monday, all under the watchful eyes of six massive statues of former kings.

The sunset gathering in Hua Hin, part of a Muay Thai Festival in the seaside resort town, broke the previous Guinness World Record of 250 by having 3,660 participants simultaneously performing the traditional pre-match dance of respect for their coach.

The sun had baked the sheets of concrete hot as the barefoot performers -- organised by the Tourism Authority of Thailand (TAT), the Royal Thai Army, and the culture and sport ministries -- filed onto the parade ground at Rajabhakti Park in front of Prime Minister Prayut Chan-o-Cha.

Dressed in red uniforms with white Mongkhon headbands, as well as white Muay Kard Chuek ropes -- the hemp wrappings fighters wore before gloves -- the phalanx of men moved in near perfect unison to the directions of famed Muay Thai fighter Sombat "Buakaw" Banchamek.

"Congratulations, you're officially amazing," said the official Guinness adjudicator, confirming the record had been broken.

"I feel really proud," said 27-year-old performer Phukrit Purimchaithanat, adding he and his fellow-cadets were glad they had pulled it off after months of preparations.

A mix of bemused locals and tourists passing through the popular resort watched the spectacle from a few rickety metal bleachers, gathering around the sides of the fenced area as a loudspeaker blared.

"It's stunning, it's crazy, also in front of the kings and everything," said Hua Hin resident Siena Cruz, 32, as she enjoyed the show with friends.

"The visual is something connected to the tradition," she said, noting how integral the pre-match ritual was to the sport.

"To be part of another bit of history for Thailand, it's bragging rights," she said of the Guinness record.

"I like to watch, but boxing is scary," said June Rubyung, who had taken her grandson to watch the performance.

The 50-year-old Hua Hin local, who lives close to the army grounds where they performed, said she knew the army cadets had been practising for a month.

"I think they're good," she said, "they do it the correct way."