Many gathered at the Guernsey Information Centre for the 4.30am start.
They were led off by the walk’s ambassador, Lt-Governor Vice Admiral Ian Corder, with first-time walker and Guernsey FC player Ross Allen.
‘The challenge of completing the walk is no less significant for sports athletes as it is for men and women generally,’ Mr Allen said.
‘I’m really looking forward to being out enjoying the fantastic amenity that our coastal path offers and will be celebrating like everyone else as we cross the finish line.
‘But, on top of the personal achievement that the walk offers, I am looking forward to being involved in a truly island-wide initiative that brings the community together in celebration of the relative freedoms that we have earned ourselves.
‘And at the end the day we will have collectively raised tens of thousands of pounds for distribution to local charities by the island’s Rotary clubs.
‘This really is a wonderful example of what we have come to know as ‘Guernsey Together’.’
Walk chairman Simon Milsted said the length of the walk was equivalent to travelling the length of a football pitch 600 times.
‘It’s a different type of goal for Ross,’ he said.
Walkers are set to arrive at Jerbourg at around 6am and then at Le Gouffre for breakfast at about 8am. They are then expected to reach Cobo at 2pm.
Families Walking Together will start from Chouet car park at noon, while the main walkers are expected through at 4pm.
The finish line at the Liberation Monument in Town. Walkers who are taking part in the Families Walking Together event or the Guernsey Disability Alliance Accessibility Walk should arrive about 4pm.
Walkers become quite dispersed towards the end, with most expected to finish between 6.30pm and 10pm.