Nine of the group completed the swim
Members of the Outdoor Swimming Society have been swimming around Burgh Island in south Devon.
Nine of the 17-strong group completed the one-mile challenge on Sunday morning with the others turning back.
It is the first of a number of Swim Safaris planned throughout the summer to introduce people to locations for wild swims around the country.
The founder of the Outdoor Swimming Society (OSS) Kate Rew said it was a "gorgeous" experience.
"It's a swim I write about in my book Wild Swim. I swim all the time and it's a new venture to see if other people want to swim with us," said Ms Rew, who set up the OSS two years ago.
The group now has 2,7000 members across the UK.
"I think a lot of people are very keen to get back into the water," she said.
Burgh Island is a small tidal island off the south coast of Devon near Bigbury.
It is home to the Art Deco Burgh Island Hotel and a pub - the Pilchard Inn.
The island is only 200m from the shore and at low tide walkers can get there on foot.