He has competed in two Coast to Coasts, run the 85km Ghost to Ghost Ultra, and more recently won the 2018 New Zealand junior men's 8km mountain run at Cardrona, near Queenstown.
Williams has no plans of slowing down any time soon. In April he will take on the Oparara Wilderness Trail Run at Karamea, and the following month the 20km Mount Oxford Odyssey.
Williams says he got into running because he was worried about putting on weight.
He was working at the Greymouth High School cafe and got paid with food. At the same time he was struggling at rugby league training, so he took up running and has never looked back.
His first taste of running was in the school cross-country. He not only won it but enjoyed the experience.
His running career could have ended when, at 16, he decided to have a go at the Ghost to Ghost Ultra marathon, completing the 85km in 10hrs 45mins.
Williams says it was a run he should never have attempted.
A friend of his father Barry Williams had suggested he give it a go, but in hindsight Williams says it was very hard.
"I was not mentally prepared for such a long run."
Running such a long distance race his mind started playing tricks on him.
"I was laughing for no reason and then I would just stop - I had no control."
Afterwards he vowed he would never take on such a gruelling event again.
Williams played league for a while but gave it away because due to his size he kept getting "smashed".
His first Coast to Coast was in 2016 when organisers introduced a category for school teams.
"Dad mentioned it and I thought it would be good to give it a go."
He talked schoolmate George Rubbo into doing the cycling and principal Andy England suggested Blake Robertson would be a good option for the kayaking section.
"Unfortunately, Blake broke his neck and we had to rope in George's brother Max at the last minute - he had two months to learn how to kayak."
Williams returned this year for his second Coast to Coast, and now holds the under-18s record for the run over Goat Pass, which he completed in 3hrs 10m this year.
England has nothing but praise for the young runner.
"Ben had the vision for the Coast to Coast. Had it not been for him and his drive and determination we would not have had teams in the annual event."
He had helped put adventure racing on the map at Greymouth High School.
"It has been an absolute delight to see him do so well with the mountain running," England said.
Williams has some good pedigree. His mother Debbie was in the New Zealand women's rugby league team and his aunty Sally features on one of the school's honour boards for athletics.
Apart from running, Williams is a keen tramper.
He finishes school this year but at this stage is still undecided on his future.
"It all depends on how my running goes, but I'm keen to get a job and save enough money up to get my helicopter's pilot licence."
Williams says selectors were out and about at the trail run he won at Cardrona a week ago and he believed there was a slight possibility of making the New Zealand team for the World Running Championships in Spain in May.
Greymouth runner Mel Aitken has already been named in the New Zealand team.
- by Viv Logie
