Motuarohia, also called Roberton Island, has the most photographed view in the bay — a short climb up the central ridge gives an aerial-style look down on two perfect blue lagoons separated by a thin spit of sand. Cruise boats stop here regularly for snorkelling and a short walk.
The island has a darker history: in 1841 the entire Roberton family was murdered here by a Maori labourer named Maketu, the first criminal trial under British law in New Zealand. Today the island is a benign place — gentle paths, clear water, and a marine reserve patch where snorkellers see kingfish, snapper and the occasional eagle ray. Bring fins; the lagoon shelves quickly into deeper water.