Four fellow teammates and their coach, Ekaphol Chantawong, remain inside, with hopes that they will be rescued on Tuesday.
Elite divers hauled 4 more young footballers out of a flooded Thai cave on Monday, July 9, authorities said, bringing to 8 the number saved in a stunning rescue mission but still leaving 5 others trapped.
People across Thailand cheered the rescue operation, including at the Mae Sai Prasitsart school where six of the trapped boys are students.
A BCRC spokesman said: "The UK divers are part of the core team, so they will be actively involved and that will include escorting each child out through the flooded passage".
Two of the boys possibly have a lung infection but all eight are generally "healthy and smiling", he said.
Alluding to that worry, the regional army commander offered his thanks Monday to the rain god Phra Pirun, imploring him to "keep showing us mercy".
"So, it's not so much how they'll be feeling in the immediate aftermath - we would expect to see some strong reactions - or not - it depends upon many factors I don't know about". Bancha Duriyapan told a news conference punctuated by applause from the dozens of Thai and foreign journalists and others in attendance.
Thai officials started the rescue operation on Sunday as weather experts predicted more rain in the coming weeks. "So I've been asking for three days".
The first four boys to leave the cave, ...
All of the rescued boys had low temperatures, but are being warmed up.
The emergence of the second batch of four on Monday evening was greeted with a simple "Hooyah" by the Thai SEAL team on their Facebook page, an exclamation that lit up Thai social media.
Their friends were full of optimism - and worry.
Somboon Sompiangjai is the father of one of the 12 boys.
"Even when my friends have left the cave, I'm anxious about their physical well-being". I'm happy being here inside, the navy Seals have taken good care.
The boys' nightmare experience - trapped in claustrophobic darkness by rising waters - resonated across the globe, riveting people both in Thailand and internationally who anxiously watched the news coming from this town along the border with Myanmar.
Witnesses say the boys freed Monday were treated at a make-shift hospital at the site, before being taken to a local hospital.
"The factors are as good as yesterday, and the rescue team is the same team with a few replacements for those exhausted", Narongsak Osatanakorn, the governor of Chiang Rai province who's leading the operation, said Monday, The Guardian reported.
More worrying, however, oxygen levels in the chamber where the boys sought refuge were falling.
Nargonsak said this phase may take longer than the previous two rescue missions, which took up to 11 hours.