The dolphin was seen and filmed over the weekend and DOC is encouraging the public to report any further sightings or provide further photographic evidence.
Other sightings have been reported in Napier in September this year and at Omaio in Bay of Plenty during May, but the Coromandel sighting is the furthest north this year.
Hannah Hendriks, a Marine Technical Advisor for DOC, says that reporting sightings of this distinctive species helps to build a bigger picture of the species' status and their movements.
"Reporting sightings helps DOC look after marine mammals by providing information about population sizes, breeding rates and movement patterns. It's particularly valuable for Hector's dolphins because there are so few of them.
"It's really exciting that a Hector's dolphin has been spotted in this area because they're generally only found in the South Island, and the related Māui dolphins only on the West Coast of the North Island. These photos are proof that the dolphins are occasionally exploring other areas of New Zealand."
They are easily identifiable from other species as they are much smaller – only around 1-1.5m in length, and their dorsal fin is round and black in colour.
Hector's dolphins are considered nationally vulnerable to extinction, with an estimated population of 15,000.
They are among the world's smallest marine dolphins and are found only in the inshore waters of Aotearoa/New Zealand.
Their identical cousins, the Māui dolphin, are a subspecies of Hector's dolphin and are only found off the West Coast of the North Island. A genetic sample is needed to tell the two sub-species apart.
Unfortunately, Māui dolphins are facing extinction with an estimated 63 individuals over one year old remaining.
Hector's and Māui dolphin are known to Māori by other names, including tutumairekurai, aihe, papakanua, upokohue, tukuperu, tūpoupou, pahu, pōpoto and hopuhopu.
If you are lucky enough to encounter one, if possible, take a good photo of it and record where and when you made the sighting.
Reporting a sighting is easy and can be done through an online reporting form, the Hector's dolphin sightings app, or via the 24-hour DOC hotline, 0800 DOC HOT (0800 362 468).
