A total of 21 children and seven staff from Brockton CE Primary School set off on their marathon and were joined by parents on the first day on Sunday, when they walked to Church Stretton.
They have been looking to complete eleven miles each day to reach their goal.
David Lockley, a teacher of Years 5 and 6, said: "We have been putting in practice walks and carrying out final preparations.
"The children, staff and volunteers have put so much effort into making this week a huge success for the charities, which were chosen by the children to benefit from the funds raised.
"These include Cyclists Fighting Cancer, Ataxia UK and Hannah's Holiday Home Appeal.
"We hope to complete the walk by 5.15pm on Saturday at Aberdovey."
Mr Lockley added "During their walk the children will be stopping overnight in village halls, church barns, a secondary school and community hall along the route.
"They will be making their own breakfasts and packed lunches.
"It was wonderful to see the parents joining us for the first day of walking to Church Stretton and for a church service.
"The children have been walking on the Long Mynd and Brown Clee, the highest hill in Shropshire, and their trek includes both lane and hill walking.
"Those taking part are aged between nine and 11-years-old, and this will be a massive challenge for them and will need them to use all their will-power and determination.
"We would ideally love to raise thousands of pounds for the three charities involved and anyone wishing to donate can do so through the justgiving.com/fundraising/brockton-ce-primary-school page.
"Those wanting to donate to Hannah's Holiday Home Appeal can do so through that charity's appeal page."