The first video of the boys, aged 11 to 16, and their 25-year-old coach was released on Wednesday, a day after the final rescue took place at the Tham Luang cave in Chiang Rai province brought international joy and relief.

It shows the boys looking thin but well, resting in their crisp white hospital beds with some wearing green surgical masks as made the peace sign or bowed for the camera.

The boys and their coach lost an average of two kilograms during their ordeal which began on June 23 when driving rain blocked their exit from the cave, but were generally in good condition, a senior health official said earlier.

Derek Anderson, a 32-year-old US Air Force rescue specialist based in Okinawa Japan, said at times the boys were put in harnesses and high-lined across rocky caverns, while also enduring dives lasting up to half an hour in pitch black water during the rescue.

"The world just needs to know that what was accomplished was a once in a lifetime rescue," Anderson told The Associated Press in an interview on Wednesday.

"We were extremely fortunate that the outcome was the way it was. It's important to realise how complex and how many pieces of this puzzle had to come together."

Chiang Rai Prachanukroh Hospital director Chaiwetch Thanapaisal said the 'Wild Boars' are strong in heart and mind.

"Don't need to worry about their physical health and even more so for their mental health," Thanapaisal said at a news conference.

"Everyone is strong in mind and heart."

The four boys and the coach, who were the last to be brought out on Tuesday had recovered more quickly than the boys rescued on Sunday and Monday, Chaiwetch said.

Three of the boys had slight lung infections and all will spend another week in hospital, Chaiwetch said.

The Thai Navy SEALS have posted footage of one of the boys being carried through part of the cave on a stretcher covered with a thermal blanket.

Two British divers found the team on July 2, after nearly 10 days underground, huddled on a small, dry shelf just above the water, smiling with relief but visibly skinny.

Rescuers from around the world including Australia, the US, Britain and other countries worked with Thai Navy SEALS to guide the group out of the cave's flooded passageways riveting the world.

It was a complex and difficult process as many of the boys could not swim and had to learn to breath through scuba gear and cope with the dark, swirling water and narrow dangerous passageways.

The rescue was not without tragedy with a former Thai navy SEAL, who was helping replenish oxygen canisters on the escape route dying on Friday.

Chiang Rai province acting Governor Narongsak Osatanakorn, who oversaw the rescue operation, has lauded the cooperation between Thai and international rescuers.

"The situation went beyond just being a rescue mission and became a symbol of unity among mankind," he said.

"Everyone worked together without discrimination of race or religion as the ultimate goal was to save the youth football team."

Plans are now underway for an interactive museum at the cave based on the historic rescue mission, while two film production companies are looking into making a movie about the miraculous rescue.

Australian Associated Press