Mike Bodger, 60, of Whakatane is halfway towards his goal of becoming the oldest person to swim Cook Strait.
He entered the water off the top of the Marlborough Sounds at 8am on Tuesday.
After swimming for five hours, he was in the middle of the Cook Strait.
Honey sandwiches, jelly beans, sports drink and warm water are given to him from a support boat every half hour.
Bodger expects to make landfall at around 6pm by Red Rocks, but that will be determined by the tides.