They are to be discharged on Thursday from a hospital in the northern town of Chiang Rai.
"Doctor Richard Harris did his utmost on the medical mission he was responsible for, but if something went wrong he needed protection", Thailand's foreign minister Don Pramudwinai told Reuters.
Adul is perhaps the best known of the boys because he was the one speaking English in the video taken inside the cave when the team members were first found by two British cave divers on July 2, almost 10 days after being trapped by flooding.
Speaking on Wednesday via Skype to Malcolm Turnbull, Dr Harris brushed off the Prime Minister's praise.
The boys were informed on Saturday about the death of former Thai Navy SEAL diver Saman Gunan.
Harris is known across the world for his cave rescue expertise.
"We said sorry to Jao Mae Nang Non", said Nippon, referring to the princess whose spirit is believed to protect the cave and which many Thais feared was disturbed by the throng of rescuers, volunteers and media during the 17-day operation. Pictures show them gathering around a picture of the diver, as they continue to be monitored in hospital.
Anaesthetist Richard Harris and his diving buddy Craig Challen, both cave diving specialists, were granted diplomatic immunity and played key roles in the rescue.
With them are six Australian Federal Police cave divers, one Defence diver and a support crew who have been described as integral to the rescue operation.
The boys are understood to have entered the cave as a part of a team ritual, where younger boys would carve their names on to the wall.
The team is recovering in a hospital in Chiang Rai.
Doctors say they are in good health following a successful three-day operation which ended July 10 when teams of Thai Navy SEALs and worldwide cave diving experts hauled the last five members of the team to safety.
Dr Richard Harris with his dive partner, West Australian vet Craig Challen.
They spent nine days in the dark, dank cave before being located by two British divers.
Thousands of people have called for Dr Harris and Mr Challen to be given the Cross of Valour, the nation's highest civilian bravery award.
"I'm getting better, (I want to eat) KFC", Adul Sam-on, 14, a stateless child born in Myanmar's Wa state, tells the camera before turning to English to thank the world for helping rescue them.
A spokeswoman for Australia's Department of Foreign Affairs and Trade declined to comment.
"Even though they are about to leave in the days ahead. they aren't as strong as a normal person, they still need to rest and improve their health, and body", he said.
They also acknowledged the "vast number" of military and civilian participants who helped in the operation, along with their Australian colleagues.
Thai navy SEALs and an global team of cave-diving experts played a key role in bringing them to safety.