The North Fiji Basin (NFB) is a shallow oceanic basin, with depths between 2000 and 4000 m, which lies between latitude 10 degree and 25 degree South and longitude 170 degree and 180 degree East. Situated at the boundary of the Indo-Australian and Pacific plates, the NFB stands between two subduction zones of reverse polarity: the New-Hebrides subduction on its western side and the Tonga. The aim of the Seapso 3 cruise of N.O. Jean Charcot (December 1985), was to delineate the recent spreading location in the North Fiji Basin, and to observe possible associated hydrothermal manifestations. For that we first have performed a large scale bathymetric and geophysical survey and then a detailed survey (complete coverage Seabeam) on two boxes. Finally, rocks sampling and hydrocast have been carried out along the axis.