Two Sunshine Coast boys say they would not be alive if it was not for the adults who risked their own lives to save them from a "brutal" rip on the Sunshine Coast on Sunday afternoon.

Tyler Reid, 11, Felix Hall, 11, and another boy were on a sandbank about 600 metres south of the flags at Kawana Beach when they were pulled into the rip.

"It was really strong. The waves were big and they were pushing us down and pulling us back," Felix said.

It is not known how long the boys were in the surf when a couple walking their dog on the beach heard their "blood-curdling" screams as the boys struggled to stay afloat more than 100 metres offshore.

"When I saw them I was just like 'Yes, we're not gonna die'," Felix said.

Rochell Blair and Jonathan Clare say they did not think twice about saving the three boys from a "brutal" rip after hearing their screams. ( ABC Sunshine Coast: Kylie Bartholomew )

Rochell Blair, 31, and her fiancé Jonathan Clare, 30, never go for beach walks without a mobile phone.

But on Sunday they had left their phones behind, and with no beachgoers nearby they had no way to raise the alarm.

In a split second, the pair dashed into the water to help the boys.

Mr Clare said by the time he reached the boys he had to decide who to help first.

"I was helping him out and then realised that Rochell was out there with the other two boys and I was like 'Oh god'," he said.

Surf lifesaver's gut instinct helps save group

Amid the treacherous conditions Ms Blair, a former surf lifesaver, was instructing the boys to stay on their backs, keep moving their arms and legs, and stay above water.

All the while she kept a safe distance "that I'm not going to get drowned underneath".

"The undertow was just insane," she said.

"You would do three strokes and you were getting pulled back five. It was crazy.

"And then next minute I turn around and there's the jet ski and I was like 'Where did this guy just come from?'"

Rescuer Scott Edwards says the three Sunshine Coast boys, including Felix Hall (L) and Tyler Reid are lucky to be alive. ( ABC Sunshine Coast: Kylie Bartholomew )

That guy was Scott Edwards, a Brisbane firefighter, surf lifesaver and long-time member of the Kawana Surf Club who was doing a roaming patrol of the coast's southern beaches.

He had followed a gut instinct to patrol the southern beaches instead of heading north towards Maroochydore.

During that patrol he had warned at least a dozen swimmers that they were not within the flags and were alongside a rip.

Then he spotted the frantic waves coming from the group.

"From the way I saw one of the young fellas go under twice, I don't think it would've been another minute or so before he would've been under," Mr Edwards said.

"He was struggling."

'Most brutal' rip rescuer had experienced

With waves crashing from every direction, Mr Edwards piled the five onto the jet ski.

But given the conditions, they all fell off. Twice.

Dave Hall (R) says parents should not assume that just because their child can swim they will be safe in the surf. ( ABC Sunshine Coast: Kylie Bartholomew )

Once back on the beach, paramedics treated the group and they were taken to hospital for observation then later released.

"Just swim between the yellow and red flags. It's just so scary," Ms Blair said.

Mr Clare, an experienced surf swimmer, said it was the most "brutal" rip he had experienced.

"I was holding onto one of the boys and it just felt like someone else was on the bottom of my legs pulling me down," he said.

"It took a good 30 seconds before we realised what situation we were in as well.

"When we started struggling that's when I went 'Well, what are we gonna do?'

"If the jet ski hadn't of come past at that time I've got no idea what we would've done. I don't want to think about it."

Tyler Reid and mum Sarah-Jane Ross thank Jonathan Clare after Sunday's rescue off a Sunshine Coast beach. ( ABC Sunshine Coast: Kylie Bartholomew )

Emotional reunion for families

On Monday, two of the boys and their parents were reunited at the Kawana Surf Club with the three adults who saved them.

Both the boys' families live in the beachside suburb, but on that particular afternoon neither knew the boys were at the beach until they had a phone call they will never forget.

Tyler's mother Sarah-Jane Ross panicked when she received that call.

"I just got a call that they were in the ambulance getting oxygen and to get there ASAP," she said.

Felix's father Dave Hall said his son was a "powerful" swimmer and Nipper "and I always assumed he was going to be safe".

"I asked him why [he was swimming outside the flags] and that he should know better, but I was more relieved he was safe than to be angry at him.

"He does know better but I think boys just don't think when they get together."

One of the boys' grandmother gives an emotional thank you to Rochell Blair, who risked her own life to save the woman's grandson and two other boys on the Sunshine Coast. ( ABC Sunshine Coast: Kylie Bartholomew )

'We just did what anyone would do'

Amid the thanks, praise, hugs and flowers being passed around the reunited group, none took for granted the reality of what could have been.

"Just the repercussions of everything, that our kids put someone else's life in danger as well," Ms Ross said.

"That was our main concern that they were okay, not just our own, because without them, ours wouldn't be here."

The boys did not hold back in thanking the rescuers.

"Thank you for saving our lives. We probably wouldn't be here without you," Felix said, as both boys added they had learnt their lesson to swim between the flags.

Rochell Blair, Scott Edwards, Sarah-Jane Ross and Jonathan Clare contemplate how different the outcome could have been. ( ABC Sunshine Coast: Kylie Bartholomew )

The Sunshine Coast couple refused to be labelled as heroes.

"I definitely had tears of emotion and thinking about my life, my family that I could've lost," Ms Blair said.

"I don't feel like a hero. We just did what anyone would do."

Mr Clare agreed and added it was the lifeguards who were the heroes.

Ms Blair, who is set to marry her fiancé in three weeks, said she had a new perspective on life.

"My family, my friends, you just hold those people a little bit closer and tell everyone you love each other because that's the most important thing," she said.