Four more of the boys were carried on stretchers out of the labyrinthine Tham Luang cave on the Myanmar border at dusk on Monday, bringing to eight the number brought out so far after two rescue pushes on successive days.
Importantly, as of the time of this writing, eight of the 13 trapped people have already been saved by the heroic actions of rescue divers and support teams.
Torrential rain had not affected conditions for the rescue operation.
"One of the things we have learned from previous research is that how young people are before they undergo an extreme experience like this is often a reasonably good predictor of how they will do later on after the event".
Rescue operations chief Narongsak Osottanakorn described Sunday's initial rescue bid as "D-Day" when it was launched, and there were fears that any one of many potential pitfalls could prove deadly.
Technology billionaire Elon Musk went into the cave on Monday and left the rescue team with a "kid-sized" submarine his company SpaceX had built, Thailand's interior Minister Anupong Paochinda said. 4.24pm: The rescued boys have been set up with IV drips and antibiotics, as well as receiving vaccines for tetanus and rabies, the Guardian reports.
Officials lavished praise on the Thai and worldwide divers who executed the unsafe rescue mission, guiding boys who can barely swim and have no diving experience through a treacherous 4-kilometre-long (2 1/2-mile) escape route that twisted and turned and rose and fell inside the mountain cave complex.
Onlookers watch and cheer as ambulances deliver boys rescued from a cave in northern Thailand to hospital in Chiang Rai after they were transported by helicopters.
Authorities have said extracting the entire team from the cave could take up to four days, but two straight days of success raised hopes that it could be done faster.
The distance from where the crew is trapped to the main entrance is about a half a mile, and the boys had to travel most of that distance underwater to reach freedom.
The safety of the divers, who have meticulously planned the mission, is also paramount.
They were found last Monday by two expert British divers. Last week, a former Thai navy diver died while preparing for the operation. He said it was out of respect for the families whose sons were still trapped in the cave.
Monday's rescue effort took about nine hours, two fewer than the day before, in a sign of growing confidence and expertise.
Oxygen levels in the caves also dropped, causing the cramped passageways to be even more deadly than before.