Whitianga is a mecca for fishing, cruisers and stargazers (remember - Mercury Bay was named by Captain Cook when he observed the transit of Mercury here in 1769).  For that reason, there are many charter operators here.

Catch Charters offer everything from fishing and diving charters to hour-long scenic tours.
The Hahei Explorer is a beautiful scenic tour around Cathedral Cove.
Cave Cruzer is a truly unique experience with live music in the Waitaia sea cave.
The Playmaker tours take in Mercury Bay including the "Hole in the Wall" and Cathedral Cove.

These are just a few of the local charter operators, many more have links and information on the Whitianga Information Centre Website .