If you are starting from downtown Auckland, the Devonport ferry is the best way to get to the North Shore. It is operated by Auckland Transport and runs every 20 minutes during peak times and half hourly off-peak. It only takes about 20 minutes, compared to driving, which could take half an hour or more (the traffic can be as bad as it gets in Auckland). There is also the alternate option of the Bayswater Ferry.
The ferry offers nice views of the city and waterfront, especially at night. To the west of the Devonport ferry terminal, you also travel past the NZ Navy facility, so you will probably see one or two (modest) naval ships. Once in Devonport, you can hike up Takarunga Mt Victoria or start along the North Shore Coastal Walk.
You need an Auckland Transport Hop card to use the ferry, and, bizarrely, you can’t get one at the terminal. So come prepared!
