A Dutch hotelier almost had the lifeboats out earlier after paddleboarding in the sea off Blackpool as heavy fog rolled in.
The man disappeared into the mist close to Manchester Square, panicking a watching member of the public who never saw him return this afternoon.
They called in the Coastguard, who launched a search as RNLI volunteers were called to the lifeboat station on the Promenade and put on standby ready to launch the lifeboats.
Paul Little, the Coastguard's station officer for Blackpool and Lytham, said rescuers could barely see the sea from the Prom - and said the paddleboarder couldn't even hear people's shouts because he had music on.
"We didn't recommend him being out in the water because if he fell off, we would not know where he was," he said.
"A member of the public was watching him and he disappeared and they never saw him again.
"They did the right thing, but he did not.
"As soon as the fog came in, he should have come in too.
"The danger is, if you do things regularly, you desensitise yourself to how dangerous it is.
"If you fall off, you could become disorientated and not know if you are paddling back to shore or out to sea."
The RNLI said volunteers were called out at 2.45pm in "poor visibility" to reports of a paddleboarder "who had set off from Manchester Square and not come back".
It added: "Our lifeboat was being prepared for launch when one of our volunteers spotted the paddleboarder. Safety advice [was] provided."
A spokeswoman said the man "stayed close to shore, which was the right thing to do, and he could see the Prom at all times".
She added: "He had done that deliberately and he was very experienced."