Sunderland forward Duncan Watmore was on the fishing boat in Barbados when it was hit, and broken in two, by a catamaran.
He managed to haul three elderly passengers out of the water from the boat just before it sank.
His father, Ian Watmore, said the catamaran had "just ploughed straight into the boat and ripped it in half".
"They saw it and just assumed it was going to go round them and, when they realised it was coming straight at them, they started yelling and screaming but nothing changed," he said.
"These catamarans are quite powerful and the blade just ripped the thing in half."
Watmore had been in Barbados in February, recovering from an operation on a cruciate knee ligament injury, when the crash happened.
One of the guests on the boat had just had a hip replacement, one could not swim and the other was over 80, his father said.
After the crash, his son "clambered up on to the catamaran" and lifted them, and the skipper, out of the water just as their fishing boat sank, he said.
The 23-year-old footballer used his T-shirt as a tourniquet for the woman's leg, which was "bleeding heavily".
It was only afterwards that "shock started to set in", Mr Watmore Snr said.
"All the guests were coming up to him and telling him what a hero he was and I think the whole thing was just very disorientating for him," he said.
The rescue had been a good test of the strength of his knee, though "not one you'd plan", he added.
It is not known how the catamaran came to hit the fishing boat but it is believed its skipper was taken away by police.
A Premier League footballer saved three holidaymakers after a boat crash, it has emerged.