They battled to hold the child's head above water as the trio struggled back to the shore.
Northland Rescue Helicopter pilot Susan Dinkelacker said she was on shift at the helicopter base in Kensington, Whangārei, when an emergency call came through around 3pm that reported children were in trouble in the water.
"When you hear it's children potentially drowning - we're hot off the mark," Dinkelacker said.
"It doesn't take long for kids to get swept out of their depth."
Within 10 minutes the Northland rescue chopper was hovering above the beach where a crowd of people had gathered.
"The sea conditions looked benign," Dinkelacker said. "It wasn't high seas."
With the tide low, Dinkelacker manoeuvred the helicopter on to the sands - which locals warned are a sink trap for vehicles - and the St John Flight Intensive Care Paramedic rushed to where the teenagers had been laid on the sand.
A mother was on her property nearby when she saw the chopper fly overhead. A Kiripaka resident said the terrified mother had sprinted to the beach afraid her son had been hurt.
The resident himself had been at home when the chopper flew close to his house.
"I thought 'holy heck what is this doing here'," he said.
"We ran down to the beach to see if anyone needed help and to work out what was going on."
When he arrived at the scene they saw the mother hugging her unharmed son, who was not involved in the incident, as well as emergency services racing to help the teenagers.
Locals who were close by had rushed to the teenagers' aid and worked tirelessly to support the emergency services when they arrived, Dinkelacker said.
"This community was amazing as they really rallied around. They were helping with transporting the patient and helping to carry equipment for the paramedic. We have huge gratitude for their quick response."
The teenage boy - the youngest of the two - was left in a serious condition from his rescue efforts.
A man who lived nearby used his 4WD to ferry the boy, prone on a stretcher, from the water's edge to the helicopter, which had relocated to the beach access by the dunes.
With his mum at his side, the teen was airlifted to Whangārei Hospital. At edition time the Northland DHB was unable to provide an update as to the boy's condition.
Dinkelacker said the slightly older patient went by ambulance to the same hospital.
The female teen was reported to be in a moderate and stable condition.
The resident who rushed down to the beach when he saw the chopper said everyone in the area was incredibly grateful the children had survived the incident.
"We are so lucky that no one died," he said. "It's so easy for people to drown at the beaches and there are no flags here."
In 2020, 69 people drowned in New Zealand waters, including one person in Northland.