Runners and walkers of all ages and abilities will charge through the Whakarewarewa Forest during the Copthorne Rotorua Off Road Half Marathon.
As well as the 21.1km half marathon, the annual event tomorrow comprises the Mitre 10 Mega Quarter Marathon Fun Run/Walk, the Red Stag Timber 5km Fun Run/Walk, Lance Lawson Little Devils 2.5km Fun Run/Walk (7-10yrs) and the Lance Lawson Little Devils 1.5km Fun Run/Walk (3-6yrs).
The half marathon is raced over two laps of a 10.5km course using scenic trails and smooth gravel forest roads. The quarter marathon is one lap of the same course.
Last year the winner of the half marathon was Gisborne's Steve Morrow who finished in 1h 24m 54s.
The fastest woman was Rotorua's Johanna Ottosson in 1h 35m 10s, who also won in 2016. The fastest Rotorua man was Dave Cronshaw who finished third 1h 30m 43s.
Event Promotions general manager Murray Fleming said what made this event unique was the "spectacular" Whakarewarewa trails.
"It's a much nicer environment [than the road] and it's not on the tarseal, so it's a much more pleasant environment. There is no other place in New Zealand that has the variety of trails, roads and infrastructure that Rotorua does. The course is stunning.
"Initially this was the Ngongotaha Half Marathon and has always been a pre-event for the Rotorua Marathon run by the Lake City Athletic Club. With the increase in traffic and the requirements of signage on the roads they moved it into the forest and asked Event Promotions to take it over. We've been running it in the forest ever since," Fleming said.
He said the half marathon course, which would be announced on race day, was "challenging but achievable".
"There's a couple of hills in it, but they're not bad."
Entry numbers are similar to last year and 1200-1400 participants are expected.
"There will be about 300 little kids and the remainder will be adults. It's a good family day out. There's always a good blend of competitive runners, but the majority are our social runners.
"A lot of people use it as preparation for the Rotorua Marathon on May 5. A lot doing the marathon will do the half here, if they're doing the half they'll do the quarter here. The feedback has always been positive, they like the forest.
"They've changed the course for the Rotorua Marathon this year to include the forest, you actually do use some of the same course."
Fleming said, as well as a sense of achievement, every participant would receive a finisher's medal, including the children.
"There are some quick kids and they just try 120 per cent."
Details
What: Rotorua Off Road Half Marathon
Where: Whakarewarewa Forest
When: Sunday, first race at 9am
Registration in main marquee at Waipa Recreation Area.
9am: Start of the Lance Lawson Little Devils 1.5km Fun Run/Walk (3-6yrs)
9.10am: Start of the Lance Lawson Little Devils 2.5km Fun Run/Walk (7-10yrs)
9.45am: Start of the Red Stag Timber 5km Fun Run/Walk
10am: Start of the Copthorne Half Marathon
10.15am: Little Devils Prizegiving
11am: Start of the Mitre 10 Mega Quarter Marathon Fun Run/Walk
1.30pm: Prizegiving