A device for transferring fluid between two floating supports anchored to the sea bottom, having a rigid central undersea pipe installed below the surface with its ends each being connected to respective ones of two supports via a flexible hose. The main portion of the rigid central pipe includes or co-operates with buoyancy elements such that the central pipe adopts, in a quasi-static rest state, a configuration of an arch, preferably following a curve such that the angles between the half-lines of the axes of the rigid pipe and the horizontal half-lines at each of its ends extending towards the other end present absolute values of less than 20.degree. and the flexible hoses present lengths and curvatures such that variations in the curvatures of the flexible hoses are suitable for compensating the movements of the floating supports.