The Marlborough District Council Harbour encompasses approximately 4200 km of water-space including all of the Marlborough Sounds and d'Urville Island. The harbour supports a diverse range of activity including commercial shipping, marine farming, tourism, and recreational boating. Major town centres include Picton, Waikawa Bay and Havelock but it is also home to many permanent residents and small communities are established throughout the sounds.
The purpose of the Harbourmaster is to ensure that Council meets is statutory obligations as the Harbour Authority to maintain a safe and navigable waterway free of oil pollution. The Harbourmaster is supported by a small team based in Picton and the Harbour's vessels can frequently be seen on the water.