The triathlon includes a 1km swim, 26km mountainbike and 11km run.
"The festival is well run and it's just a great local event with plenty to do for spectators."
XTERRA Rotorua Festival media manager Nicola Carter said they expected close to record numbers on Saturday.
"It's going to be a pumping atmosphere this year."
She said the festival included stalls along the lakefront, plenty of food and activities for children.
"The kids can do the 11km walk and dad can run the half-marathon."
The festival begins at 8am with an 11km or 21km trail walk or run followed by a 26km mountainbike event at 9am.
The feature multisport triathlon begins at 11am for individuals and 11.45am for teams.
Participants can still enter at www.xterra.co.nz or at Distinction Rotorua Hotel from 3pm to 9pm tomorrow.
The cost ranges from $30 for the 11km run or walk to $165 for entry in the triathlon team event.