Three younger girls, thought to be 7-8 years old, were not out as far but were not strong swimmers. Two of them were wearing lifejackets.
"They were struggling, they weren't happy," Lauren said. "I think they would have eventually been pushed in ... and hit the rocks [as well]. I grabbed the two with the lifejackets and the other girl I held. I got behind them and pushed them out of the water. It was difficult because the current was so strong but I could still stand."
Meanwhile, Hannah was dealing with the boy, who had been cut up on the rocks.
"The man wasn't quite on the rocks. I swam past him and walked up on to the rocks to the boy. I held him so he wasn't getting bashed against the rocks any more. I carried him back to the dad and swam back to shore," Hannah said. "I had the boy under my arm and I was kind of dragging the man behind me.
"If we hadn't been there, I think they probably would've been pushed over rocks and out to sea. They were out of their depth and they didn't really look like they knew what they were doing."
Once ashore, the sisters received hugs and thanks from the three girls. The man seemed in shock, they said.
The group left the beach in a hurry and their identities were unknown to their rescuers. The teens' mother, Anna Williams, who was at the other end of the beach during the drama, was proud of her girls.
"That's what lifesaving is all about. They just drop and go, that's the way they're trained. I'm obviously very proud ... they know what to do and they're out there helping people."
Check beach for lifeguards
Weekday lifeguards have already vacated Mangawhai Heads, as well as a number of other popular northern beaches. It's something Anna Williams, the mother of two lifeguards, says is an accident waiting to happen.
Funding for weekend lifeguards comes from councils, which set the dates their beaches are manned.
Weekend guards are usually volunteers, who work longer through the summer season.
The two beaches most guarded are Piha and Muriwai, with lifeguards every day from December 2 until March 7.
Other beaches vary, with most having weekday lifeguards from December 16, but ending on different dates.
Mangawhai Heads has one of the shortest runs, and is manned seven days a week only from December 23 until January 17.
To see which beaches are staffed by lifeguards, visit findabeach.co.nz.
• Do you know the people rescued? Contact us at newsdesk@nzherald.co.nz.
