The army want 2,000 military personnel with high levels of physical fitness and good behavioural records to march in three traditional processions during His Majesty the King's coronation ceremonies in May.
The parades will take place over three days starting May 3, considered the highlight of the coronation events.
The army's Ordnance Department is working on selecting the men, with some advice given by army chief Apirat Kongsompong.
Participating troops must be well-built and have "good personalities" to ensure the ceremony proceeds in an "elegant and grand manner in honour of the King", Gen Apirat said.
They will be required to go through training sessions and have a thorough understanding of various marches.
According to the organisers, 133 soldiers will feature in the first procession from the Temple of the Emerald Buddha to the Phaisan Thaksin Throne Hall in the Grand Palace on May 3.
They will carry royal items including phra suphannabat, a golden sheet with the King's name inscribed on it, and his royal seal.
The second procession on May 4 will comprise 234 soldiers.
They will accompany the King from the Amarin Winitchai Throne Hall to the Temple of the Emerald Buddha, where His Majesty will declare himself the upholder of religions.
On the same day, the King will preside over a ceremony paying homage to former monarchs at Prasart Phrathep Bidorn, a castle located inside the Grand Palace.
A percussion-based marching rhythm will be used for both processions.
The third and largest procession will feature 1,368 men accompanying the King as he performs a liap phranakhon ceremony on May 5.
The parade will be led by a band playing six songs composed by the late King Bhumibol Adulyadej.
This ceremony is expected to last about three hours.
Preparations for the three parades began on Wednesday when 42 senior officers from the armed forces attended a three-day training session.
The officers are well-versed in traditional parades and have been informed about the coronation ceremonies in detail, the organisers said.
Their joint marching rehearsals are scheduled to be held in April.