The Nelson Endurance Series: Ironman Challenge, at Tahunanui Beach, Nelson New Zealand, is organised by Nelson Triathlon & Multisport Club.

The Ironman Challenge offers swimmers a 1.3km and 3.8km open water swim in an around-the-buoys and point-to-point course format and is the third of four swims in the Nelson Endurance Series.

Swimmers in the 3.8km option will head north from Tahunanui Beach before reaching the dolphin navigation marker and turning south to follow the south east tow of Haulashore Island around to the second navigation marker to the south of the island before returning back to the beach and crossing the finish line.

Swimmers in the 1.3km option will walk to the Richardson Street steps before swimming back to the finish line at Tahunanui Beach.