Several operators leave from Whitianga Wharf for the cliffs, coves, sea caves, and marine life around Mercury Bay and Te Whanganui-a-Hei Marine Reserve. The coast is the point here: white rock, blue water, small beaches, and the chance of seals or passing dolphins.
Choose a short early or late sailing if you are only passing through. Longer cruises make sense if Cathedral Cove access is awkward or you want to see the coast from the water rather than from the walking track.