The New Zealand ferry company Interislander, owned by Toll Group Australia, operates three vessels connecting Wellington on the northern island with Picton on the southern island. Interislander’s daily ferry service across Cook Strait provides a vital transport link between New Zealand's north and south islands for passengers and their vehicles, commercial vehicles and rail freight. The journey takes about three hours and has been described as one of the most beautiful ferry trips in the world.

Interislander’s largest vessel is the RoPax vessel Kaitaki, chartered from Stena RoRo. Kaitaki means challenger in Maori and the vessel has been on a long-term bareboat charter since 2005. The ship can accommodate up to 1,600 passengers and is the largest ferry in New Zealand waters.