The team of firefighters and supporters will be cycling 56 miles from Louth Fire Station to Brayford Pool in Lincoln.
Then, they will swap their pedals for paddles and kayak 16 miles down the River Witham through to Kirkstead Bridge in Woodhall Spa.
Finally, the team will put on their trainers and run all the 26 miles all the way back to the Louth - the equivalent of a Marathon - before the Sun sets.
The team’s efforts, on Monday July 18, will all be in aid of The Firefighters Charity, which provides support to serving and retired firefighters and their families.
If you would like to sponsor the team ahead of their challenge and help them to smash their £2,000 target, visit www.justgiving.com/teams/louthfire.