A procedure for remote sensing of mesoscale ocean dynamic processes has been proposed by Munk and Wunsch [Deep Sea Res., 26A, 123–161 (1979)]. It is based on the measurement of acoustic travel time variations between fixed sources and receivers distributed on the boundary of a large ocean area. Inverse theory is invoked to estimate the structure of the interior sound velocity field from travel time perturbations along individual ray paths. In this paper we present the results of a 48-day multipath stability experiment that demonstrates sufficient path stability to enable ocean acoustic remote sensing using this technique. A 220-Hz phase encoded signal with 64-ms resolution was transmitted at 10-min intervals between a moored source and a receiver at a 900-km range. Ray paths are clearly resolved, unambiguous, and identifiable. [Work supported by ONR.]