Twelve boys and their football coach who survived a highly dangerous and dramatic rescue from a flooded Thai cave spoke publicly of their incredible ordeal for the first time on Wednesday at a press conference that was beamed around the world.

The "Wild Boars" team members looked healthy and happy as they answered questions about the nine days they spent in the dark before being discovered by members of an international rescue team.

A packed crowd greeted the youngsters after they were discharged from hospital in Chiang Rai, and watched as they played with footballs on a small makeshift pitch before taking their seats.

"It is a miracle," Wild Boars footballer Adul Sam-on, 14, said of the rescue, as the boys were gently quizzed about their terrifying experience.

Coach Ekkapol Chantawong said the relative strength or weakness of the boys did not determine the order in which they were evacuated. He added that the boys would ordain as monks in honour of the former Navy Seal who died during the mission.

The team had no food at all until they were found deep in the complex, surviving only on water that dripped down the side of the cave.

But doctors said all 13 were in good physical and mental health after recuperating in hospital.

The briefing was tightly controlled, with experts warning of possible long-term distress from the more than two weeks they spent trapped inside a cramped, flooded chamber of the Tham Luang cave in Mae Sai district in Chiang Rai province..

The Public Relations Department in Chiang Rai solicited questions from news outlets in advance, which were forwarded to psychiatrists for screening.

Interest in the saga has been intense, with film production houses already eyeing a Hollywood treatment of the drama.

Doctors have advised families of the players, aged 11 to 16, that they should avoid letting them contact journalists for at least one month.

Families of the youngsters have eagerly awaited their homecoming.

The presenter of the televised news conference said the boys would return home on Wednesday night for the first time since emerging from the cave.