Ian Bell grabbed a branch after falling into the River Wear when it was in spate in April, but the branch snapped and he was washed away.
The boy, who had been playing with two friends near his home in Sunnybrow, County Durham, was found days later after a major operation involving police, fire, search specialists and the RAF, joined by hundreds of members of the public.
A diver found Ian’s body snagged on a tree root under the water three miles downstream from the spot where he fell in.
Pathologist Dr Paul Barrett told the inquest at Crook Civic Centre that the cause of death was “immersion in water”. That was different from drowning, in that the shock of the cold or panic could have led to Ian’s death.
County Durham coroner Andrew Tweddle recorded a verdict of accidental death.
Chief Superintendent Andy Reddick, who led the police operation to find Ian, said officers were alerted 50 minutes after he fell in. He was playing in a fast-flowing stream close to where it met the Wear when he slipped and was quickly pulled into the main river.
After the hearing Mr Reddick said: “There’s no-one to be blamed – it was just lads being adventurous.”