Doak said just this week Facebook memories alerted him to a sighting this time three years ago.
The latest encounter was spotted by Scott Turton, who posted pictures of the fish on Facebook.
"I'd say a pretty young one, must've been 6-7 metres long, by itself also, another spotted about 6 weeks ago other side of the Bay but even bigger. Really awesome to see," Turton said.
Turton said the fish was near the Nine Pin. The whale shark is a slow-moving, filter-feeding carpet shark and the largest known extant fish species.
They occasionally visit northern New Zealand waters from November to March. Most sightings are made in February. The Department of Conservation says those found in New Zealand have been between 3m and 15m.
Early this month jetskiers near Whangamata, riding towards the Aldermen Islands, spotted a whale shark.
The distinct markings and giant, wide mouth helped identity it.