On a cold, wet Sunday morning, 1000 brave souls take on Bloody Long Walk

The 35-kilometre trek wound down the coastline past Thirroul and Bulli Beach, with checkpoints scattered along the way handing out water and providing first aid support to those in need.

Participants were raising money to fight mitochondrial disease, a genetic disorder which "robs the body's cells of energy" and is often terminal.

Trevor Vizgoftv said he had found someone to chat with to walk with as they passed the eight-kilometre mark and called the walk "great".

"I met a nice bloke here, who's keeping me walking reasonably fast," he said.

"I'm here to help other people mainly, I'm a blood donor with 528 donations ... which I enjoy."

Mr Vizgoftv who also participated in the Great Illawarra Walk said he would "fire on" and hopefully improve his speed throughout the day.

Susan Hodgson, who has participated twice previously, woke up at 5.30am to be a part of the walk and said she braved the conditions not just to support the cause.

"I just do it for my own doing of it ... I just wanted to do it myself," she said.

"It is a lot cooler temperatures this time for sure."

Manning one of the five checkpoints along the way was Georgia Taylor.

"This station just has water and we have a medical stuff set up, other checkpoints should have some fruit handed out as well," she said.

"We're set up right next to the beach near bathrooms and a car park so accessible to everyone as well."