Four boys were rescued Monday, the Thai navy confirmed, bringing the total rescued to eight since operations began Sunday.
Chiang Rai governor Narongsak Osotthanakorn said at a press conference on Monday that the effort would involve the same divers. Sunday's mission took nine hours and plenty of energy, with each child being accompanied by two divers along the way.
Another, of indistinct origin, asked their teacher not to give them a lot of homework.
Officials have yet to confirm the identities of the four boys freed, and Narongsak Osottanakorn, the head of the rescue operation, said their identities were being protected out of respect for the families of those still trapped inside the cave. "More personnel" were being used than on Sunday.
Speaking to NBC's "Today" on Monday, he said: "The main challenge is that we are dealing with young kids that are in no way trained to do cave diving".
The urgent and unsafe effort has involved the boys diving through the cave's tight and twisting passages, guided by experienced divers.
Thailand's navy SEALs say all 12 boys and their soccer coach have been rescued from a flooded cave in far northern Thailand, ending an ordeal that lasted more than two weeks. The message, like most posted by the SEALs, ended with the fighting cheer adopted from the U.S. Navy: Hooyah.
The operation to rescue the boys, ages 11-16, and their 25-year-old coach by having them dive out of the flooded cave began Sunday morning, with expert divers entering the sprawling complex for the complicated and unsafe mission. But the rescue was prodded into action by the threat of a fresh round of rains and falling oxygen levels in the cave.
Earlier Monday, Narongsak said the four rescued the day before were in good spirits.
Chiang Rai health officials have told the Thai media that the families of the children can see them later tonight but "no hugging, no kissing" until their blood results are known.
The extraction of the four on Monday followed a similar pattern to the previous day, with the youngsters emerging in quick succession just before nightfall after navigating a treacherous escape route of more than four kilometres. They were in good condition in hospital, officials said.
The boys and their coach set out to explore the vast Tham Luang cave complex after soccer practice on June 23, and got trapped when a rainy season downpour flooded the tunnels.
A massive worldwide search operation was launched and it took 10 days to locate the boys, who had taken shelter on a dry slope deep in the complex.
UPDATE 0841 ET: The rescue operation has been suspended for the night in Thailand.
Extracting everyone from the cave could take up four days, but Sunday's success raised hopes that could be done.
A team of 90 expert divers - 40 from Thailand and 50 from overseas - has been working in the cave system. He said the metal tube of the device is "light enough to be carried by 2 divers, small enough to get through narrow gaps" in the cave system.
As the perilous rescue operation continues, Xylem still has three employees on site and is air-lifting in new pumps that might be able to boost pumping capacity if there are still people left in the cave when they arrive.
Getting to and from where the boys are has been an exhausting round trip, even for the experienced divers.
Though it rained again Sunday, it did not affect the water levels in the cave, said Narongsak Osatanakorn, the leader of the command center in charge of the rescue operation.
In an indication of how unsafe the journey can be, a former Thai navy diver died in the caves on Friday.
The hazardous bid to rescue the boys - aged between 11 and 16 - started unexpectedly on Sunday when the rescue team said conditions were flawless for the evacuation.