The Thai boys evacuated from the flooded cave have paid their respects to the former Navy Seal diver who died trying to save them.

The 12 youngsters and their football coach were not told that Saman Kunan had drowned ahead of their dramatic rescue from the Tham Luang cavern just days ago.

His dramatic death convinced the Thai authorities for the need to call back the British cave-diving experts to lead the 'mission impossible' to save the boys, the Daily Mail reports.

Some of the rescued soccer team members get emotional as they consider the Thai Navy SEAL diver who died. (Photo / AP)

The youngsters bowed their heads in respect to former Petty Officer Kunan and posed with a picture of him at their hospital ward, where they are being treated for malnutrition, pneumonia, ear infections and exhaustion.

One boy covered his face as he cried.

Ekkapol Chantawong, the 25-year-old football coach who led the ill-fated outing into the cave, wiped away tears with a clenched fist.

"All of the boys who were evacuated from the cave have been informed of the death of one of the rescuers," Dr Jesada Chockbamrungsuk, who is in charge of their treatment, announced.

"All of the boys cried and were in tears when they found out.

"The survivors expressed their thanks to the Thai Navy Seal by bowing to his picture.

"The boys all promised to be a good person and lead a good life to honour him."

He added: "We told them about the death of Navy Seal Kunan as part of the process of preparing the boys to go back home and to lead normal lives."

The rescued soccer team members pose with a sketch of the Thai Navy SEAL diver who died while trying to rescue them. (Photo / AP)

Hundreds of mourners paid their respects to the 37-year-old at a special ceremony attended by high-ranking military officials and a representative of the king at the Wat Ban Nong Khu temple in his home town of Chatuphak Piman yesterday (Sat).

Kunan was awarded the Knight Grand Cross (First Class) of the Most Exalted Order of the White Elephant medal and posthumously promoted to Lieutenant Commander.

Dressed in their hospital robes, the youngsters were also seen enjoying a sit-down meal together.

Crowded around a table, the boys ate traditional Thai dishes of rice, pork and soup.

The 12 boys and their football coach also watched a recording of the World Cup final.

"Given that the final will be broadcast quite late our time, and we want the boys to rest and not to be looking at screens too much, we will probably record the final and show it to them later," said an official the Chiang Rai Prachanukroh Hospital.

France played Croatia in the World Cup final in Moscow on Sunday, at 10pm in Thailand.

Some of the rescued soccer team members eat a meal together in a hospital. (Photo / AP)

FIFA had invited the boys and their coach to attend the final in Moscow, but they can not go for medical reasons.

The 12-member Wild Boars team and their coach spent more than two weeks trapped inside a flooded cave in the northern province of Chiang Rai.

They have been recovering in hospital since they were rescued over three days last week and will discharged on Thursday.

The boys, aged 11 to 16, and their 25-year-old coach had planned to explore the Tham Luang cave complex for about an hour after soccer practice on June 23.

But a rainy season downpour flooded the tunnels, trapping them.

Two British divers found them on July 2, squatting on a mound in a flooded chamber several kilometres inside the complex.

Rescuers then had to work out how to get them out through the flooded tunnels.

All 13 were brought to safety in a perilous rescue organised by Thai Navy Seals and an international team of cave-diving experts.

The rescue was greeted with joy by some of the world's biggest football clubs.

Last week, Manchester United invited the Wild Boars to watch a match at their Old Trafford ground.

About 4000 volunteers were on Sunday taking part in a clean-up of the area around the Tham Luang cave.

A park area around the mouth got trampled by the hundreds of rescuers, and media workers, who flocked to help with the mission and to report on it.

Authorities have closed the cave for now but hope to reopen it later as a tourist attraction - with sufficient safeguards in place to make sure no one gets trapped again.

Former Navy Seal, Saman Kunan, died while trying to rescue kids trapped in a cave in Chiang Rai.