Guy Cribbs set off from Cherbourg at about 0830 BST
Two men claim to have become the first to windsurf more than 75 nautical miles (138.8km) across the Channel.
Guy Cribb from Poole, Dorset, and current World Champion Frenchman Antoine Albeau set off from Cherbourg in France at about 0830 BST.
The pair took just over six hours to reach land in Poole through stormy seas, with Mr Cribb describing the journey as "epic".
They are raising money for the Ellen MacArthur Trust.
The pair have so far collected more than £6,000.
Looking at his hands, Mr Cribb said: "I've got a couple of cuts but nothing to worry about.
"What a mission. That was the hardest thing I've ever done.
"Out in the Channel where the weather was huge and it was really rough, one of the boats was half sinking, baling out water all the time and we lost cameras. It was epic."
Earlier, he said he had always wanted to take part in a really big challenge.
"At some points we're going to be nearly 40 nautical miles from land in some of the busiest shipping lanes in the world. It is a mad thing to do."
The Ellen MacArthur Trust aims to support children suffering from cancer, leukaemia or other serious illnesses by introducing them to sailing.