There will also be a wealth of up-and-coming New Zealand junior triathletes competing in the event, including 2017 Tinman Triathlon winner Josiah Ney and Hannah Knighton, who was the fifth fastest junior woman in last year's ITU World Triathlon Grand Final.
Osborne said he always looked forward to racing in his "own backyard" and the event would be helpful in preparing for this year's Asia-Pacific tour.
"I haven't done it for a couple of years, but when I was right into road triathlon it was always the week before nationals and a good hit-out. It's always a good form finder, which is the reason I'm doing it again, I just need to have a race before I crack into the overseas stuff.
"The aquathon is probably the most horrendous way to have an aquathon, going run then swim, but that's all part of it - it's a good way to test yourself and make sure you get your pacing right.
"I always enjoy racing at home, it's not something you get to do a lot in a year. This and Xterra Rotorua are the only two triathlons I do at home. It's always good to get out in front of all your family and friends," he said.
Race director Marie Heaphy said entries were sitting at 385 in total, including the maximum of 150 in the children's events. Adults online entries close tonight,but they can still enter on the day with a $10 entry fee.
The festival is being held on Saturday and Sunday at the Blue Lake Reserve on Tarawera Rd and has the option of five events: aquathon, open water swim, kids triathlon, sprint triathlon and 5km fun run/walk.
Sign up at rats.org.nz/events/blue-lake-multisport-festival or enter on the day.
