Take a cruise across the Fovreaux Strait to Stewart Island on board the Real Journey catamaran. During the hour-long crossing, you'll see all sort fo wildlife, especially seabirds, so make sure to bring your camera and binoculars. For more info on what to see on Stewart Island see https://www.stewartisland.co.nz/.
Real Journeys are currently offering adults $20 off a return journey.