"I was supposed to run with a team member in the 85km event - we were going to do a marathon each. But a few days before [the race] he pulled the plug."
He said race director Paul Charteris talked him into doing the 60km distance solo.
"I ran the 60km and really enjoyed it. I got the bug from there and have enjoyed it ever since."
Last year, he set out to tackle the 100km race but pulled up at the 85km mark.
"So I was determined to nail that 100km this year," he said. "I was race number four this year, so the fourth person to enter."
He trained hard up until Christmas but saw a need to help organise the event, with Charteris and his team.
It meant he could not run the 100km tomorrow, as he will be organising and helping participants, so he decided to do it solo last month.
"I just did it solo. I thought 'I'm not going to put all this training to waste'," he said.
He set out on a Saturday running the first 35km barefoot, before successfully working his way towards the finish of the course in Kawerau.
"That satisfaction will stay with me for the rest of my life," he said about completing the 100km course. "It is life changing to be honest."
Day said he considered himself to be an average Joe, not an elite athlete, and the achievement had taught him a lot.
"It is ultimately the success of working hard for a goal at the end of the day. It flows through to massive benefits in the rest of your life."
Day said he was enjoying being part of the organising team for the huge event tomorrow, which includes more than 200 volunteers and 850 participants.
The event will begin at 6.30am at the Redwoods Visitor Centre on Long Mile Rd.
The sixth annual Tarawera Ultra is also race three of the inaugural Ultra Trail World Tour. This features 10 races in Europe, Asia, North America, North Africa, Australia and New Zealand. Entry numbers have doubled from last year and the race features some of the international superstars of the sport.
What cyclone? That won't stop us
Even Cyclone Lusi won't be able to stop competitors lining up for the Tarawera Ultramarathon tomorrow.
Race director Paul Charteris said the popular event would go ahead even if the storm hits Rotorua during race day tomorrow.
The cyclone is expected to reach northern New Zealand late tonight or early tomorrow, bringing heavy rain and winds, before it moves south.
Charteris said all the tracks on the 100km course, between Rotorua and Kawerau, drained well and the storm would not affect the 850 participants.
"The rain has no impact on the runners at all," he said.
"What it does do is make it a bit unpleasant for the spectators and volunteers."
He said they recommend participants to take a rain jacket with them on the run, which they can wear while stopping at aide stations.
Charteris said all the tracks were well prepared for the sporting event and the volcanic soil drains really well.
For live updates of the race check the Rotorua Daily Post website.
