Résumé : Sloshing refers to the motion of the free liquid/gas interface inside a partially filled container subjected to an external excitation with a consequent motion of the system center of gravity. Several parameters related to the fluid container, the fluid properties, the excitation levels, and the gravitational environment govern this phenomenon. Moreover, it is a significant cause of disturbance in embarked reservoirs. In this paper, it is shown that the absolute liquid/gas interface position ηA during moderate sloshing (i.e., in the absence of splashing and wave breaking) can be measured over the full surface domain by the Reference Image Topography technique. It is applied to sloshing in steady and in transient regimes, underlining its potential. The simultaneous measurement of the liquid/gas interface position, in several points, has allowed us to identify swirling regimes and to evaluate the spatial distribution of fluid damping.