The 2018 Ironman World Championship was a long distance triathlon competition held on October 13, 2018, in Kailua-Kona, Hawaii that was won by Patrick Lange of Germany and Daniela Ryf of Switzerland.

It was the 42nd edition of the Ironman World Championship, which has been held annually in Hawaii since 1978.

[a] The championship was organized by the World Triathlon Corporation (WTC).

For Ryf it was her fourth consecutive Ironman World Championship win.

For Lange it was his second consecutive.