Leyland couple Craig and Jackie O’Neill, and their friends Jay Cartwright and Helen Wilson, were enjoying a day out in Hvar, Croatia, when they decided to hire a boat to go the nearby Paklinski Islands.
On their way back to shore, choppy waves capsized the boat, throwing the group and all their possessions into the sea.
As the boat sank and Craig was unable to keep himself afloat, he accepted that he was going to die.
But then an unknown Australian man risked his own life, jumping in from a nearby excursion boat, to save Craig and Jackie.
Without the heroism of the unknown man, Craig believes that he would have died on that day.
“It was a lovely, calm, and hot day,” said 42-year-old Craig - who grew up on the Broadfield estate in Leyland.
I had already taken in a lot of water and I thought this was it for me and I accepted that I was going to die.
“On the way back it was calm as well but as we came out from the islands into open water it got really bad.”
A huge wave hit the boat from the side and chucked the four of them into the sea, with Jackie initially getting stuck under the boat.
The dad-of-two added: “Everyone was hysterical. We got our hands on the capsized boat to stay afloat and tried to wave down a passing boat about 25 metres away with about 20 people on it.
“Our boat then started to sink, so Jay made a dash for it.”It was at this point that Craig noticed a man from the passing boat take to the water.
The former Wellfield High School student said: “Some guy dived in and swam over to us and said I can only take one of you, so Jackie went with him.
“I was in big trouble then.
“After the boat had sunk we were in open water and I’m not a very strong swimmer.
“I had already taken in a lot of water and I thought this was it for me and I accepted that I was going to die.”
The Australian man had noticed what was going on and said to Jackie that “if we don’t go and get him right now he’s going to die”.
Craig said: “He told Jackie to get on his back and shout to me to swim towards them. I think a wave took me towards them as I was there in no time.”
Craig then got onto the man’s back, who then carried both Craig and Jackie to the boat, where Jay had earlier managed to swim to on his own.
Helen was rescued by Croatian lifeguards, who took her back to Hvar harbour.
Leanne O’Neill, Craig’s sister, said: “It was just terrifying, I have never heard of anything like it.”
“I felt sick. It was a long day of thinking and waiting for my partner Lee to go get them from the airport.
“When they came in my house Craig just grabbed me and held me tight and Jackie was in tears with Lee holding her.
“The story was horrible I was crying while they was going through everything, I cannot believe how lucky they are to be alive.”
Craig now wants to find this unknown Aussie hero.
“The only thing I did to thank this man was give him a nod,” Craig said.
“I want to thank him properly. I accepted I was going to die and he saved my life.
“Afterwards he was cool as anything drying himself off like it was nothing. I want to know what went through his mind at the time.”
Jackie O’Neill, 51, Craig’s partner of the last 20 years, said: “The guy that jump in for us was average built with an athletic body, had thick dark hair and a tanned complexion.”
Leane said: “What a hero this man is, my family mean the world to me and that’s why we are all so desperate to find him.”
Craig added: “There’s a lot of stuff going on in the world and people like him are amazing and need to be recognised.”
The group have taken to social media to try and find the Aussie hero, with Craig’s post being shared over 400 times. Australian media are also getting involved in the appeal.
Do you know who the mysterious Aussie swimmer is? Contact Craig at firstname.lastname@example.org