Mercury Bay Museum is the place to understand why this stretch of coast matters. Its exhibits cover Polynesian navigator Kupe, local Maori taonga, James Cook and the Endeavour, the wreck of HMS Buffalo, kauri timber, gum digging, fishing, and ordinary life around the bay.
The museum sits in an old dairy factory near the wharf, so it pairs neatly with the ferry and a harbour walk. It is small, but it gives Whitianga more substance than the summer beach-town surface suggests.