Tuwharetoa and Ironman New Zealand have reached a commercial deal on the use of Lake Taupo for the annual swim, cycle and run competition but say the details remain confidential.
Tuwharetoa Maori Trust Board says the central North Island lake is a taonga (treasure) to the iwi and revenue from commercial activities will be invested back to its people.
As part of its Treaty of Waitangi settlement the tribe owns the lake bed, but public access is guaranteed.
Legislation has been passed which gives the iwi the right to license commercial users of the lake, which means it is entitled to charge fees.
The Ironman event takes place on 2 March.