Most members of the Thai youth football team rescued from a flooded cave will have their heads shaved and don robes to be ordained as novices in a Buddhist ceremony on Tuesday.
Their coach will also receive monk's orders. One of the boys will not join the ceremony as he is a Christian, the BBC reported.
The group will spend nine days living in a monastery, a tradition for males in Thailand who experience adversity.
They were trapped for more than two weeks before a dramatic rescue.
The boys were all released from hospital last week and are said to be in good health after their ordeal in the snaking caverns of the Tham Luang caves of northern Thailand.
This step is intended to be a "spiritual cleansing" for the group, the BBC report said.
"They should spend time in a monastery. It's for their protection," Seewad Sompiangjai, grandfather of Night, one of the rescued boys told the BBC earlier. "It's like they died but now have been reborn."
Thai officials said the boys will start the process by having their heads shaved, before attending a robe ceremony on Wednesday.
They will stay in different monasteries until August 4 meditating, praying and cleaning their temple and the length of time they will spend doing this -- nine days -- is a nod to a Thai lucky number.
One of the boys, Adul Sam-on, will not be joining the rest of the "Wild Boars" football team as he is a Christian. Their coach Ekkapol "Ake" Chantawong, 25, will join them for the same period of time but as a fully fledged monk rather than a novice.
The coach had spent time in a monastery as a novice before this.
The extraordinary story of the group's rescue has been followed by millions worldwide since 23 June, when they walked into the cave after football practice -- only to be trapped by sudden monsoon floods.