Stock Photo - The Interislander Ferry Between Picton, South Island and Wellington, North Island, New Zealand. Picton is a small town in the north of South Island where you catch the interislander ferry from Picton Harbour, South Island to Wellington, North Island. It is a busy little harbour town with endless water based activities and the opportunity for a stunning cruise up the Queen Charlotte Sound. Time your ferry departure from Picton to Wellington right, however, and you won't need to do a tourist cruise as the ferry spends the first 45 minutes winding its way out of the Queen Charlotte Sound, before crossing the Cook Strait.