Dylan Roxburgh, 13, said the group had been training 20 minutes before the incident, so he felt confident they knew what to do.
"We had just had tube rescue training. I took the 6-year-old boy and swam him in. He stayed calm."
Dylan said his parents and his coaches were proud of him.
"I'm pretty happy about how it went for my first rescue," he said.
The rookies will graduate to begin lifeguard training when they turn 14.
Only 11 rescues have taken place at Ocean Beach during the summer. This was the only incident there at the weekend.
Lifeguards were watching between 200 and 300 people at Mangawhai Beach during the weekend, the conditions were calm and there were no rescues.
Waipu Cove had a quiet weekend, with calm water. The club captain suspected most people had headed to Ruakaka to watch a surf lifesaving tournament there. Ruakaka Beach was packed with competitors and spectators for the Northern Region Championships, the second-largest surf lifesaving tournament in the country.
Check out photos of all the action at the surf lifesaving Northern Region Championships held at Ruakaka Beach over the weekend on page A11.