Nurses chatted with them and the boys responded with the customary Thai sign of respect - hands pressed together while bowing the head.
The 12 boys and their soccer coach lost an average of 2 kg (4.4 lbs.) during their ordeal but were generally in good condition and showed no signs of stress, a senior health official said earlier.
The boys would have to stay in the hospital for up to 10 days, hospital director Chaiwetch Thanapaisal told the news conference.
Doctors have put the 12 boys, aged 11 to 16, and their 25-year-old football coach in quarantine while they are being tested for infectious diseases they may have contracted inside the Tham Luang cave complex. Three have slight lung infections.
The water pumps failed, and commander Chaiyananta Peeranarong heard shouts of alarm as the final stage of an unprecedented operation to rescue 12 Thai boys and their coach from a flooded cave nearly tipped into disaster.
In a video that emerged hours after the group were discovered, he said: "I'm Adul, I'm in good health", and offered a traditional Thai "wai" greeting, a trademark of his manners, his teachers say. "The coach was the one to choose".
Adul became a symbol of hope after images of him were broadcast around the world, showing he and his teammates were alive in the Tham Luang cave. "The divers carried them out and they were wearing wetsuits to keep them warm", Thai navy SEAL chief Apakorn Youkongkaew said.
The Thai football team who were trapped in the cave.
"My wife actually grew up with the Thai Navy SEAL that died in the cave".
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The former governor of Chiang Rai province, Narongsak Osatanakorn, the local official in charge of the rescue operation, told ABC News some of the boys were too weak to really walk.
Narongsak said global rescuers led the final phase of the risky mission.
Onlookers at the junction in front of Chiangrai Prachanukroh Hospital watch and cheer as ambulances transport the last rescued schoolboys and their coach from a nearby helipad to the hospital.
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A large rescue operation got under way on Sunday, with divers extracting the team in batches of four and five over the course of three days. Relatively mild weather and a massive effort to pump out water created a window of opportunity.
"My job was to transfer them along", he said, adding the "boys were wrapped up in stretchers already when they were being transferred" and were monitored at regular intervals by doctors posted along the kilometres-long escape route. Before their discovery, they survived by drinking water dripping into their cramped refuge. They were all were rushed to the hospital mostly because of fear of infection.
Deputy Prime Minister Prawit Wongsuwan said on Wednesday the operation was nothing short of a miracle.
"This is clearly a time of grief for the Harris family, magnified by the physical and emotional demands of being part of this week's highly complex and ultimately successful rescue mission".