Interislander is New Zealand's original Cook Strait ferry service, connecting Wellington in the North Island to Picton in the South Island. Operating since 1962 as a division of KiwiRail, it plays a crucial role in inter-island transport, facilitating both road and rail connections. The service runs multiple daily sailings year-round, with trips taking about three hours. Annually, it transports nearly 1 million passengers and a significant volume of vehicles and freight.

The fleet includes two main vessels, Kaitaki and Kaiārahi, which together handle the busy route. Interislander offers onboard amenities such as stunning views, locally sourced food and beverages, cinemas, and premium lounges. The service supports tourism as part of KiwiRail's Great Journeys New Zealand brand and engages in community and environmental initiatives. With a rich history and a commitment to efficient transport, Interislander continues to be a vital link for travelers and freight across the Cook Strait.