The 13-year-old boy remains in hospital with injuries to both his legs after being bitten by the shark at a popular swimming spot in Vaucluse, in Sydney's east, yesterday afternoon.
A speedy response followed from emergency services, about 4.20pm, including police officers applying two medical tourniquets before administering first aid on board their boat while taking him to nearby paramedics.
The teenagers were jumping off a six-metre rock into the ocean when the attack occurred.
Superintendent Joseph McNulty said at least one of the boys' friends jumped into the water and pulled him out after the attack, while the others called for emergency services.
"The actions of his mates who have gone into the water to pull him out have been nothing but brave.
"Those actions of those young men are brave under the circumstances and very confronting injuries for those boys to see, but I suppose that's mateship."
The teenager under went surgery overnight and remained in a critical condition in the intensive care unit at Randwick Children's Hospital today, where he was surrounded by family.
The Department of Primary Industries and Regional Development is working to identify the species of shark involved in the attack, with initial reports suggesting it was a bull shark.
The incident happened near Nielsen Park and Shark Beach, a popular swimming spot for families that has a netted area in Sydney Harbour.
Supt McNulty believed extra fresh water in the harbour after recent heavy rain, combined with the splashing effect from jumping off the rock face, created a "perfect storm" for the shark attack.
"I would recommend not swimming in the harbour or our other river systems across NSW at this time … it's not a good time to swim," he said.
Agriculture Minister Tara Moriarty said: "This is a tragic shark attack on a young boy having a swim on a Sunday afternoon in a harbour beach in Sydney's east," Ms Moriarty said.
"Our thoughts are with the young boy and his family. I understand there were also a lot of young people on the beach at the time of the attack. Our thoughts are also with them."
Multiple swimmers have been attacked by sharks in Sydney Harbour in recent years, including a young woman who was bitten on the leg at Elizabeth Bay in early 2024.
Avid surfer Mercury Psillakis, 57, died when he was attacked by a shark while swimming at Long Reef Beach on Sydney's northern beaches in September.
Swiss tourist Olivia Mulheim, 25, was killed by a shark two months ago while swimming at a remote beach on the NSW mid-north coast.
