A cooperation framework has been established as part of an agreement signed by the International Triathlon Union (ITU) and IRONMAN.
The two organisations reached a deal following a series of meetings, involving ITU President Marisol Casado and IRONMAN counterpart Andrew Messick.
The Memorandum of Understanding will aim to further develop and grow triathlon, according to the ITU and IRONMAN.
It will aim to ensure the ITU is recognised as the singular International Federation leading the sport of triathlon, while IRONMAN competitions will be sanctioned as international events.
The deal comes after IRONMAN acquired Lagardère Sport’s endurance division, which saw five ITU triathlon events, four marathons and several cycling competitions move under the IRONMAN umbrella, in 2016.
The agreement also focuses on several other key topics, including standardised rules, further collaboration on anti-doping efforts and a single set of regulations across triathlon and IRONMAN events.
It will also look at relations between National Federations, sanctioning and collaborative marketing initiatives to grow the sport at age-group level.
"The best way to grow triathlon, and improve the sport at all levels, is to do so together," Casado, a member of the International Olympic Committee, said.
"Continuing strong collaboration with IRONMAN will serve to further evolve triathlon across the world.
"I look forward to many more fruitful meetings, and creating the best possible environments for athletes, following this cornerstone moment."
Messick believes the agreement, described as "historic" by the two organisations, will be "pivotal" for the development of triathlon.
IRONMAN sanctions a series of long-distance triathlon events as well as other variants of the sport.
As part of the partnership, the ITU and IRONMAN will work towards a single set of rules for long distance triathlon events from 2018.
IRONMAN will also leverage ITU resources in certain ethics-related matters, such as technological fraud, code of conduct and manipulating events.
"Our collaboration with the ITU is of considerable importance for the prolonged and continuous growth of triathlon," said Messick.
"We share a common goal, have worked well together in recent years, and have developed trust in the ITU leadership group.
"I believe that the productive conversations that led to this milestone are pivotal for the continued progression of triathlon."