Cave rescue experts have said it could be safest to simply supply the boys where they are, and wait for the flooding to subside. That could take months, however, given that Thailand's rainy season typically lasts through October.

Experienced divers are wary of taking out the boys through the dark and dangerous waters still in the cave, especially since they are untrained.

"We are talking kilometers of transport under the water with zero visibility," said Claus Rasmusen, a certified cave diving instructor based in Thailand who has been helping Thai SEAL team with logistics. "It's difficult."He said it was awkward, but possible, to teach them minimal skills.

"Nobody will teach anyone a full cave course, but trying to get them comfortable with masks, with the breathing, (is) completely different," he said. "Creating an environment that can make them safely get away, that's feasible."

AP