Two of the three girls said they did what others would have done in the circumstances.
They feared the victim was going to be drowned in the ferocious attack by two men, high on drink and drugs, and only did what they hoped others would do if they were in the same situation.
A crown court judge rewarded them for helping the victim in Wrexham.
Natasha Bostock and Tia Platt, 13 at the time but now 14, said that they did not feel like heroes.
"I could not believe it," said Natasha. "They were punching, kicking and stamping on him, and they were holding his head under the water."
Without a thought for their own safety they went down to the River Gwenfro and shouted at the attackers to stop.
Paul Loose, 24, and Ryan Roberts, 18, fled as the girls approached and they then helped the victim Jason Mee, 26, from the river.
They took him to some nearby steps, gave him jumpers to keep him warm, and waited with him until police and an ambulance arrived.
Loose and Roberts, both from Wrexham, pleaded guilty to wounding. Loose was jailed for 28 months. and Roberts received 20 months youth custody.
Schoolgirls who confronted two men carrying out a violent river attack have modestly denied they are heroes.