A 16-year-old boy has been rushed to hospital after he was found unconscious on a beach at the Georges River in Sydney's south.
Emergency services were called to Keith Longhurst reserve in Kentlyn, near Campbelltown, just before 1pm with reports a teenage boy had been pulled from the river.
A NSW Ambulance spokesman said seven crews responded to the scene, including a rescue helicopter.
Emergency crews had to walk almost two kilometres through remote bushland to get to the boy, who is understood to have suffered a medical episode while he was in the river.
Responding paramedics were told the boy managed to leave the water before he collapsed on the beach and lost consciousness.
He was winched from the beach by helicopter and taken by the helicopter to Liverpool Hospital.
NSW Ambulance Inspector Ziggy Hamann said the rescue was complicated and the boy was "very lucky".
"Given that this young man was unconscious when we arrived, we had some grave concerns for his welfare," Inspector Hamann said.
"Time is a critical factor with drownings and water-related accidents.
"The terrain and distance were additional factors that presented a real challenge to our paramedics, so it's fair to say that this young man is very lucky."
The boy regained consciousness before he was taken to hospital.
He remained in a stable condition on Tuesday afternoon.