But the governor supervising the mission said earlier that mild weather and falling water levels over the last few days had created optimal conditions for an underwater evacuation that won't last if it rains again.
Rescue operation chief Narongsak Osottanakorn said in his latest press conference that each child will be escorted by two divers and the first is expected to arrive at 9pm (local time).
"I talk to (the families) everyday and they would like us to bring their kids out but I said it has to be minimum risk". Floodwaters have been drained as much as possible, Osatanakorn said.
Authorities are also continuing to look for other ways out for the boys - including drilling through the cave so they can be extracted without making the perilous five-hour dive all the way to the cave's entrance through narrow, pitch-dark passageways filled with muddy water.
One player writes: "I'm doing fine, but the air is a little cold but don't worry".
"Night loves Dad and Mom and brother, don't worry about me". Tell my brother to be ready to bring me fried chicken. "With love." The name reference could be of a waiting relative.
One boy named Mick wrote: "Don't be anxious, I miss everyone".
Retired admiral sworn in as U.S. ambassador to South Korea
US President Donald Trump , right, meets with North Korean leader Kim Jong Un on Sentosa Island in Singapore. According to some reports , Pompeo may make another visit to North Korea this week for more talks.
While a boy called Nick writes, "Mum and Dad, I love you and Toi".
Saman resigned from the Thai military in 2006 before working at Bangkok's Suvarnabhumi airport, according to a post on the Thai Navy SEALs Facebook page, which said he was a triathlete and a "skilled and able diver". Monsoon flooding cut off their escape and prevented rescuers from finding them for nearly 10 days. Monsoon flooding cut off their escape and prevented rescuers from finding them for nearly 10 days as the only way to reach them was by navigating dark and tight passageways filled with muddy water and strong currents.
Though Gunam had retired from Navy service and was now employed as an airport security officer, he volunteered to help rescue the boys and their coach, and he was one of 28 Navy officers on the scene that are trained as specialists on sea, air and land (SEAL), the Bangkok Post reported. They had been practicing wearing diving masks and breathing, in preparation for the possibility of diving.
But if heavy rains start again, divers will try to take the boys out right away.
More than 100 chimneys are being drilled into the mountainside in a frantic bid to reach a Thai youth football team trapped in a cave complex below, the head of the rescue mission said today. But there are still sections of the cave that are flooded and would require anyone traversing them to dive.
The round-the-clock rescue efforts have prompted some Thais to ask why they went in the cave at all, and whether they deserve to be called heroes or were merely reckless.
The danger of their situation became clear when a former Thai navy diver died after delivering air tanks to the group on Friday.
A former member of Thailand's elite navy SEAL unit died during a dive on Thursday night, a grim turn in what began two weeks ago as an outing to celebrate the birthday of one of the boys.