Sally Smith and Rachel Davies, from Ruthin, will aim to walk over 70 miles in just 24 hours from April 30 to May 1.
Supported by Rachel’s husband David, they will set off from Aberdaron at 11am on Saturday, April 30.
They are doing the challenge in memory of Olivia Alkir and for Wales Air Ambulance. The Wales Air Ambulance helicopter flew Olivia’s two friends to Stoke Hospital for emergency surgery. Sally is a registered volunteer for the charity and Rachel and Dave also support them.