Tiritiri Matangi Island Transportation

Unless you have your own boat or are ready to hire one, the only way to reach Tiritiri Matangi is by the Kawau Kat hydrofoil service that leaves Auckland for the island via Gulf Harbour daily in high season, or five times weely in low season.

Fares are under 60 NZD RT, with discounts for students, backpackers, seniors and children.
There is a small surcharge for those who plan to stay overnight, therefore return on a different day. If you belong to the latter category, the company will check if you have booked accomodation before selling you a ticket.

While it is advised that you book in advance, in much of the year, away from public holidays and weekends, you could actually just show up on the morning of departure and get your ticket.