The races will feature an open-water swim and duathlon at Lake Wiritoa, plus the individual and team triathlons around the multisport clubrooms in Anzac Parade.
Much like local events, competitors will swim the Whanganui River, bike north up State Highway 4 towards Upokongaro, then run along the riverside in the Kowhai Park area.
The championships will cater for five age groups from under-12 up to under-19, as well as paratriathletes.
Sport Whanganui chief executive Danny Jonas said that week in 2017 would attract 600 athletes, along with the schools' coaches, supporters and families.
"Not only will the event act to boost local pride through enabling our community to experience another great national event, but it will also foster key national and local relationships and enable us to showcase our city and region.
"All parties involved are hugely excited at the opportunity to host this national sporting event and we'd like to express our sincere thanks to the many groups that supported us during the comprehensive proposal process."
Tri NZ's chief executive Craig Waugh is confident Wanganui will host a successful 2017 championships.
"Regional centres have proven in recent years they are best suited to successfully hosting the event and Gisborne and Taupo have built on this.
"We have no doubt Wanganui will provide excellent infrastructure, accommodation and a safe and fair course for all competitors.
"It's also clear the region will get totally behind the event and deliver a great experience for everyone involved."
