The blend was created following the world's first circumnavigational swim of the 100-mile coastline of Islay, Inner Hebrides.
Explorer's Cask is made up of whisky from all eight of Islay's operational distilleries.
Explorers Club members Chad Anderson and Justin Fornal, along with fellow swimmer Johnnie Mundell, completed the expedition in just eight days last year.
Chad Anderson, Explorers Club member, described the expedition as "epic" from start to finish.
He said: "Facing the blistering cold of the North Atlantic for eight straight days was one of the greatest challenges I've faced but an amazing adventure, which has produced a unique whisky that will raise money for a great cause.
"I'd always been a fan of Islay's smoky single malts and, as a whisky lover, an island with eight distilleries was a must-visit destination.
"However on arrival I was blown away by the scenic landscapes, the wide variety of wildlife and the warmth of the people."
Marrying for nine months, the whisky is now on pre-sale with 145 bottles available to those who enjoy the taste of adventure.
With a quarter cask in tow, the adventurers started at Ardbeg Distillery and made their way clockwise around the Queen of the Hebrides.
They took in seven more distilleries before returning to Ardbeg to celebrate their historic achievement.
The expedition was inspired by Alfred Barnard, who walked round the island by foot in the 1880s while writing his canon, The Whisky Distilleries of the United Kingdom.
Whisky is one of Scotland's most valuable commodities with visitors from all over the world coming to the country to experience an authentic Scottish dram.
VisitScotland believes the expedition will encourage visitors to make their own adventure to the island.
Home to eight working distilleries, Islay is best known for its peaty, smoky whiskies, which many consider to be the best in the world.
David Adams McGilp, VisitScotland regional director, said: "With its beautiful landscapes, world class seafood and incredible whisky offering, Islay is a fantastic place with something for everyone.
"We were delighted to help these daring explorers and I hope their adventure, along with this this rare, blended malt, will inspire visitors from across the world to enjoy the wonders of Islay for themselves."
A film crew followed the explorers and a documentary will be released later this year.
All money raised from the sale of the Whisky will go to the Royal National Lifeboat Institution.