There's also a 2km under-10 fun run, 5.5km and 10.5km trail runs and walks, a half marathon, a stand-alone 9km paddle and 31km mountain bike race, as well as a 42km duathlon.
The duathlon is proving especially popular, with gun mountain bikers Sam Shaw and former single speed world champion Garth Weinberg expected to duke it out at the front of the field, along with fleet-footed Whakatane runner Dan Jones.
The premier 50km multisport race contains a host of contenders, including Whakatane's Sam Clark, Nelson's Trevor Voyce, Hawke's Bay's Luke Osborne and Australian Jarad Kohlar. Rotorua's Nic Leary and two-time winner Elina Ussher head the women's field, with Christchurch-based Dane Sia Svendsen and New Zealand surf lifesaving representative Danielle McKenzie others to watch out for.
Another former surf lifesaving representative Michael Buck is in a team with transtasman rower Shaun Quincey, while former swimmer and triathlete Lydia Hale makes her off-road debut this weekend.
Gellatly has also introduced a dedicated paddle-boarding division in the 25km multisport race, with last year's 9km SUP paddle champion Victoria Stuart (Auckland) returning to take on the 4.5km paddle, 15km mountain bike and 5.5km run as well.
Former duathlon world champion Dr Mat Brick will also race, along with talented swimmer and son Grover, while newly-appointed Sport Bay of Plenty chief executive Heidi Lichtwark is showcasing her organisation's "more people, more active, more often" motto by running the half marathon.
Races in the Whakarewarewa Forest start at 9am on Sunday, with the multisport events starting at Tikitapu at 10.45am. Late entries will be taken at the Registration Expo during 3pm-6pm on Saturday at the Holiday Inn, Rotorua. No entries will be taken on the day.