Little did they know their short excursion would drag on for weeks and change their lives forever.

Due to the monsoon rains, the cave was quickly flooded and the group was trapped inside, leading to Thailand's biggest-ever rescue mission involving more than 1,000 people from all over the world.

Australian divers Dr Richard Harris and Dr Craig Challen, who were instrumental in the rescue of the Wild Boars soccer team, were subsequently made joint Australians of the Year for their heroic efforts.

It's one of those feel-good stories, where the group persevered, thanks partly to meditation, for 10 days without food, before being miraculously discovered and then rescued safely against all odds, through difficult terrain and strong flood currents.

Now alive and well one year on, the boys have become semi-celebrities, having appeared on the Ellen Show in October and played a friendly football match at the 2018 Summer Youth Olympics in Buenos Aires.

Many of them have had a social media boost since then. Fifteen-year-old Ekkarat Wongsukjan and 17-year-old Pornchai Khamluang have almost 150,000 followers on Instagram.

A movie called The Cave produced by Thai-Irish director Tom Waller featuring some 300 local and international cast members is expected to be released in September, while a deal with Netflix has been made to bring the story to life, although it remains unclear if the production will be a mini-series or a movie and when it will be released.

Rumours have circulated that each boy received 3 million baht ($A139,656) for the Netflix deal.

Things have undeniably looked much brighter for the boys, many of whom come from underprivileged backgrounds. Three of the boys and the 26-year-old coach who were previously stateless were also granted Thai citizenship a few months after their cave ordeal.

Despite their newly found fame and fortune, the boys are still the same to their friends and families.

"I am very proud of him. He did not change. He still wants to become a professional player. When he's back from school he is meeting his old friends and they are still playing together as a team," said Thanaporn Promthep, mother of 14-year-old Duangpetch Promthep.

"We play football and futsal together during breaks between classes. It's still the same. He [Nattawut Khamsong] still has time for me," said Puvadech Khamngoen, 14, Nattawut's close friend.

"The kids are still the same even though their lives have completely changed. They still obey the coaches. No one shows off their new-found fame. We're like brothers," said Pichai Apichai, one of the coaches of the Wild Boar team to which the cave boys belong.

Since no interviews are allowed with the boys - they have granted exclusive rights to direct contacts to SK Global, a US-based entertainment firm behind Hollywood blockbusters such as "Crazy Rich Asians" - testimonies only come from people close to them.

"We're doing everything we can to keep things as normal as possible. They do not receive special treatments, and no one really talked about the incident at school," said Kanet Pongsuwan, headmaster at Mae Sai Prasitsart School where five of the cave boys are studying.

The only special thing is the extra classes they have on weekends and holidays so they can catch up with their classmates when they were away, stuck in the cave, recuperating at home, and serving as Buddhist novices last year to express their gratitude for being rescued, according to the headmaster.

Despite the resumption of normal life, other children may feel the group's luck was unfair.

"I have heard that some students feel jealous of the boys' fame and fortune, which happened simply because they were stuck in a cave. But there has been no serious problem between the children so far," said Pasita Chaisilapin, Prajak Sutham's teacher.

Many other kids on the Wild Boar team remain stateless and very poor, another coach pointed out. Without Thai citizenship, it's impossible for them to play football at a national level.

As the sensational rescue mission has changed the boys' lives, things have also changed at the formerly unknown cave itself.

No longer muddy without proper facilities, the area around the cave has been revamped as a tourism site, with a museum showcasing arts related to the rescue and souvenir vendors setting up tents to sell T-shirts with "Tham Luang" - the name of the cave where the boys were trapped - on them.

"Let's take a photo with our hero," a tourist from Bangkok told his family in front of the museum, referring to the statue of Saman Kunan, the former SEAL who died during the mission.

On weekdays, hundreds of tourists, mainly from Thailand and neighbouring Myanmar, visit the museum and the area surrounding the cave. On weekends, there have been more than 1,000.

But the number is expected to skyrocket when the cave, which remains closed for safety reason, re-opens. It is not immediately known when the local authorities will recondition the cave to make it safe for tourists to explore.

"I can't wait for the cave to open so I can explore it. I want to see what it's really like," said Alisa Boonmee, a tourist from the north-eastern province of Udon Thani.

Australian Associated Press