Conservation of threatened large sharks and management of shark-human interactions requires an understanding of shark occurrence and movement patterns. Here, we present the first catch, movement and behaviour data of adult bull sharks, Carcharhinus leucas, in New Caledonia. Amongst six adult C. leucas tagged with passive acoustic tags, four females were caught in coastal waters while males were only found at an isolated oceanic barrier coral reef over 100 km from the nearest river mouth. Two females were monitored in the southern New Caledonia lagoon for 707 and 208 days respectively and displayed classical transient behaviour and sporadic short-term residency around a coastal reef bay, with movements in and out a river detected prior to spring. Adult C. leucas in New Caledonia may develop a sex-based spatial segregation with an atypical presence of adult males in oceanic environments, probably influenced by the unique estuarine-marine continuum of the New Caledonian great lagoon.