This is the moment a group of swimmers twice ignore a man shouting there was a shark in the water before they spotted a dark shape in the water beneath them.
The holidaymakers were swimming in the sea off the Gwynedd coast in Wales when they saw a shark in the water.
As one of the men was in the water at the time, he frantically scrambled back to his wakeboard before being pulled back aboard a boat, reports North Wales Live.
The group then watched the massive creature – estimated to be 20ft long – slowly meander under and past their boat and jet skis.
One shouted: "Look at the size of that!"
The visitors were on a weekend trip to Abersoch on the Llŷn Peninsula, Gwynedd, and headed out into Tremadog Bay towards Porth Neigwl (Hell’s Mouth) before anchoring up under the towering cliffs of Trwyn Llech-y-doll.
Jonathan Rigg, director of a Rochdale company offering residential care for young people, was in the boat at the time. "It was quite amusing, actually," he said.
"There were loads of jellyfish in the water and we were taking a look when one of the group shouted 'shark!'. It were a joke, of course: we were just messing around.
"But then moments later, there was another shout of 'shark!'. This time it came from a walker on the clifftops who was looking down on our group. You always get people shouting things from the shore and we didn’t take much notice.
"But then we saw it, right next to us. The lad in the water was sh**ing himself and got out as soon as he could. The shark swam under the boat and the jet skis. It was almost the same size as the boat, which is 23ft long."
The creature was a basking shark, which is Britain's largest fish and can reach the length of a double-decker bus.
Despite its size, this shark feeds on tiny prey, catching zooplankton by opening its mouth and allowing water to flow over its enlarged gill slits.
They can be found in British coastal waters between May and October, and during the winter months, they migrate south as far as North Africa.
As the UK waters warm with the changing climate, some species may come closer to shore as they feed on plankton, which thrives on sunlight and blooms as water temperatures rise.
Marine expert Frankie Hobro, owner of Anglesey Sea Zoo, Brynsiencyn, said in the video, the man in the water did not need to panic as basking sharks are harmless.
"They have no fear of humans or anything else in the sea," she said. "They just see us as big fish and will happily approach swimmers and paddleboarders."
