The 12 Wild Boars are seen lying on their beds, some wearing surgical masks, waving and making the ‘peace sign’ hand gesture.
None of the boys were heard speaking in the footage.
One of the boys has a lung infection, with the group all in quarantine for the next few days.
Parents of the first eight boys rescued have been able to visit their children for the first time. But they couldn’t hug their children as they were forced to stand seven feet (two metres) away and wear protective suits as a precaution.
The 12 boys and their coach have lost an average of 4.4lbs (2kg) during their ordeal trapped inside the flooded Tham Luang cave.
They are currently in quarantine over fears they could have been exposed to disease from rats or bats.
The boys will need to stay in hospital for 10 days before 30 days recovery at home. It is not thought they will be in quarantine the whole 10 days.
Thongchai Lertwilairattanapong, a health department inspector told reporters one boy from the last group rescued on Tuesday had a lung infection and they were all given vaccinations for rabies and tetanus.
Prime Minister Prayuth Chan-ocha asked that the boys be given time to recover.
Mr Prayuth said: “The important thing is personal space.
“The best way is not to bother them and let them study.”
The group ventured into the vast cave complex in the northern province of Chiang Rai after soccer practice on June 23 and were trapped when monsoon rain flooded tunnels, due to the rainy season starting early.
They were lost for nine days before British rescue divers discovered them on July 2, sitting on a ledge in a half-flooded chamber.
Getting them out – which involved teaching boys as young as 11 who were not strong swimmers to dive through narrow, submerged passages – proved a monumental challenge.
A former member of Thailand’s navy SEAL unit died during a mission in the cave on Friday.
Rescue mission chief Narongsak Osottanakorn revealed the boys nearly ran out of oxygen inside the cave, making the need for rescue even more urgent.
The commander of the navy SEAL unit that oversaw the rescue, Rear Admiral Apakorn Yuukongkaew, hailed the international effort.
He said: “We are not heroes. This mission was successful because of cooperation from everyone.
“For SEALs, this is what we were trained for. The navy has a motto: ‘We don’t abandon the people’.”
Official help came from Britain, the United States, Japan, Laos, Myanmar, China and Australia, a government document showed. There were volunteers from Denmark, Germany, Belgium, Canada, Ukraine and Finland.