Kayaker Marc Nieuwenhuys' lonely journey down River Murray becomes depression's antidote

Instead, he has realised, the battle was over the moment he broke out of his day-to-day routine and began preparing for the trip.

Rather than being a lonely journey, then, his adventure has shown how much support exists for anyone brave enough to open up about their inner demons.

He has spent the past three months making friends along the length of the river, spreading messages about the importance of mental health and living in the moment.

"Talking about it, that was the start of my recovery," he said at Mannum on Friday.

"I'm a different human being today, a different person to who I was.

He has attended two bucks' parties and stayed in strangers' shacks; but has also spent whole days with no mobile phone reception, the splash of his paddle in the brown water almost the only sound around.

"I wanted to wake up every morning and say 'this is what I'm going to do today'," he said.

"It took a lot of time for that space to become available to me, mentally, a lot of weeks.

"I guess that was the start of being able to rebuild how I wanted to be."

He began planning the journey on a whim.

He was kayaking with mates in Albury, New South Wales, when he floated past a marker labelled with the distance to the Murray Mouth: around 2200 kilometres.

Instantly, out loud, he told them he was going to do it - "there was never a discussion about it".

He did not own a kayak and had never tried any such feats of endurance.

Within days, word of his decision got around and people started opening up to him about their own mental health issues.

"For whatever reason, people feel comfortable talking to me," he said.

"It's like I've given them permission."

His Facebook page, Talking About a Lonely Journey, now has more than 19,000 followers, and he said the posts he publishes have changed people's lives.

Although his kayak journey will end at Goolwa this Saturday - he is due to arrive around 2pm, and hold a celebration at the Fleurieu Function Centre from 6pm - he hinted that his mental health mission would go on for a long time yet.

"My wellness now is the result of the people around me, their kindness, generosity and the genuine, honest conversations I've had," he said.

"I'm inspired by them being inspired."