Previously, the citizen survey conducted in connection with local fishermen, excursionists, and dive instructors, revealed through testimonies the potential presence of essential functional areas (such as pupping, nursery or feeding grounds) for the great hammerhead shark life cycle in Rangiroa and Tikehau lagoon, confirming the need to explore these inland seas. But the task is not simple when venturing further into remote areas. Reconnaissance and prospecting campaigns were carried out based on the areas identified during the citizen survey. A base camp was established in the "sector", an isolated and practically uninhabited area of Rangiroa atoll. Accompanied by local guides, members of the association, the objective was twofold: to identify the features of the area (currentology, temperature, type of habitat, species encountered) and to prospect for potential functional habitats using non-invasive methods. Attention was directed to the observation of behaviour of interest (passage, hunting or parturition scenes) and of presence of juveniles. In the case of juvenile sightings, the accuracy of species identification is a difficult task due to the known risk of confusion with other hammerhead shark species at this early stage. Further forays into the lagoon will be necessary in the future to unveil the secrets that these pristine areas hold in the ecology of the great hammerhead shark in the Central Pacific.