James Beattie, who is now a first-team coach at Leeds, helped save two children from a yacht which crashed into a chain ferry in Poole harbour, Dorset.
A woman could be heard shouting "get my children off" while the damaged boat was taking on water.
Former England international Beattie jumped over the safety barrier with three other men to help pull the children up and out of the yacht, as well as the mother.
Beattie later replied to a man who thanked his selfless act on Twitter, saying: "Current too strong for that little yacht. Glad the family are OK. Acted on instinct while too many people get their phones out to video. Crazy!"
Another man on board, believed to be the father, was helped out by a passing boat who threw him a line.
Beattie isn't the first footballer in recent months to have been involved in an aquatic rescue, with Sunderland's Duncan Watmore saving a group of pensioners in Barbados after a speedboat incident in March.
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